Hi card,
Welcome … and I’[m glad you found us 
I’m sorry to hear that your Tuft & Needle mattress didn’t work out for you although it does use good quality materials that would be suitable for your weight range. I’m not sure if you still have it or not but it may be worthwhile checking the support system you are using under the mattress just in case it’s not providing suitable support because if the foundation is bending or sagging then it could be some or all of the cause of your back pain. If you still have it you can try the mattress on the floor to see if it makes any difference and if it does and you sleep better with the mattress on the floor then the issue would most likely be your foundation.
While it’s not possible to “diagnose” mattress comfort issues on a forum with any certainty because they can be very complex and there are too many unique unknowns, variables, and complexities involved that can affect how each person sleeps on a mattress in terms of “comfort” and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) or any “symptoms” they experience … there is more about the most common symptoms that people may experience when they sleep on a mattress and the most likely (although not the only) reasons for them in post #2 here.
As you probably read on the forum Zinus mattresses are Chinese imports that tend to use lower quality/density and less durable materials and I would generally avoid them.
While I can certainly help with “how” to choose … It’s not possible to make specific suggestions or recommendations for either a mattress, manufacturers/retailers, or combinations of materials or components because the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort”, firmness, or PPP or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
There is more about the 3 most important parts of the “value” of a mattress purchase in post #13 here which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on suitability, durability, and all the other parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
While again nobody can speak to how any specific mattress will “feel” for someone else or whether it will be a good “match” in terms of comfort, firmness, and PPP because this is too subjective and relative to different body types, sleeping positions, and individual preferences, sensitivities, and circumstances and you are the only one that can feel what you feel on a mattress … outside of PPP (which is the most important part of “value”), the next most important part of the value of a mattress purchase is durability which is all about how long you will sleep well on a mattress. This is the part of your research that you can’t see or “feel” and assessing the durability and useful life of a mattress depends on knowing the specifics of its construction and the type and quality of the materials inside it regardless of the name of the manufacturer on the label or how a mattress feels in a showroom or when it is relatively new so I would always make sure that you find out information listed here so you can compare the materials and components to the durability guidelines here to make sure there are no lower quality materials or weak links in a mattress that would be a cause for concern relative to the durability and useful life of a mattress before making any purchase. This is the part of a mattress purchase that I can certainly help with.
Ravenswood:
The materials they list for the Ravenswood meet the durability guidelines for your weight/BMI range but I would check to make sure that the mattress is only 10" thick to confirm that none of the layers inside the mattress are missing in their description. If the mattress is only about 10" thick and you have confirmed that there are no missing layers and you have done some careful testing on the mattress (hopefully using the testing guidelines in the tutorial) and are confident that it’s a good “match” for you in terms of comfort, firmness, and PPP and it also compares well to any other finalists you are considering based on all the other parts of your personal value equation that are important to you then it would certainly be worth considering as a purchase.
Green Choice Bliss:
These are also Chinese made mattresses and the Bliss uses 3.5" of 3 lb memory foam which certainly doesn’t meet the durability guidelines and I would avoid it.
Doctor’s Choice Euro Top:
This mattress also uses good quality materials that meet the durability guidelines relative to your weight/BMI range and there are no lower quality materials or weak links in this mattress that would be a reason for concern relative to the durability and useful life of the mattress so once again if you have done some careful testing and are confident that it’s a good match for you in terms of comfort, firmness, and PPP and it compares well to the other finalists you are considering based on all the other parts of your personal value equation that are important to you then it would also be well worth considering as a purchase.
I’m looking forward to your comments and feedback after your visit.
You can see my comments about the Helix mattress along with many of the other what I call “simplified choice” mattresses in post #2 here and post #1 in the same topic would be well worth reading as well. The Helix mattress includes 2" of 1.8 lb polyfoam in the comfort layers which is the minimum polyfoam density I would suggest for those that are in a BMI range under 30. They also use 1.5 lb polyfoam in the base layers of the mattress which is a little under the minimum density I would normally suggest in the guidelines and that I would normally like to see in a mattress in this budget range and is also a little lower density than many of the other simplified choice mattresses but with 5.5" of materials and components above it the deeper layers would have less effect on durability for someone that is in a much lower BMI range like yourself so it’s not something that I would consider to be a weak link in the mattress in your case.
When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
I would also keep in mind that any specific mattress may be the “best” match for a relatively small percentage of people, a “good” match for a larger percentage, and an “OK” match for a larger percentage yet but many online mattresses including Helix have a good trial period and return policy so you can try them in your bedroom instead of a showroom with little risk (outside of the time you spend sleeping on it and/or returning it if that becomes necessary or any costs involved in the return process) so if it’s not a “good enough” match for you in terms of comfort, firmness, and PPP you can just return it and try another mattress if your choice doesn’t turn out as well as you hoped for. Once again though you will only know whether it’s “good enough” and you won’t know whether it would have been better or worse or how it compares to other mattresses that you could have purchased instead that you haven’t actually tried in person. This is one of the disadvantages of buying a mattress online that you can only try “one at a time” vs local testing in a store where you can compare many mattresses side by side at the same time.
I would still pay attention to the quality and durability of the materials in any mattress you are considering and make sure that they meet the minimum suggestions in the durability guidelines for your weight/BMI range because lower quality materials will tend to soften and break down more quickly which can result in the more rapid loss of the comfort and support that was the reason you purchased a mattress in the first place so you may find you aren’t sleeping as well on a mattress that uses lower quality and less durable materials even if you have only slept on it for a year or two.
Once you have narrowed down your options to a list of finalists that are all choices between “good and good” and you have confirmed that none of them have any lower quality materials or “weak links” in their design and if at this point there are no clear winners between them (which is usually a good indication that you have done some good research) then you are in the fortunate position that any of them would likely be a reasonable choice and post #2 here can help you make a final choice based on any local testing you have done, your more detailed conversations with each of the online options you are considering, your personal preferences, your confidence about PPP and the suitability of each one, their prices, the options you have after a purchase to fine tune the mattress or exchange or return the mattress (or individual layers in some cases) and any costs involved, any additional extras that are part of each purchase, and on “informed best judgement” based on all the other objective, subjective, and intangible parts of your personal value equation that are most important to you.
I’m looking forward to finding out what you end up deciding … and of course to any other comments or questions you may have along the way that I can help with.
Phoenix