Hi Edvard_Grieg,
As you probably know … the tutorial post has most of the information, steps, and guidelines you will need to make a great choice but when you are in a higher weight range then you will be harder on any mattress and the quality/durability of the materials will be an even more important consideration than it would for those that are in a lower weight range and post #3 here and the other posts it links to about heavier body types would also be well worth reading.
The choice between memory foam and latex is a personal preference and some people will prefer one and some the other. Either way … it would be important to make sure that there are no weak links in any mattress you are considering relative to your weight. There is more about differences between memory foam and latex in post #2 here but your own personal testing and experience is the best way to know which one or which combination of materials you prefer.
Many of the newer generation gel memory foam variants have a faster response and are less temperature sensitive than the non gel memory foam variants. While many people tend to prefer this because it has less of an “stuck in the mattress” feel and has benefits in terms of temperature regulation and motion restriction … there are others who prefer the slower responding and more “enveloping” versions of memory foam. This again would be a personal preference.
I don’t think that many people would be able to resist the temptation either 
It’s good to see that you are considering the quality/density of the materials in your mattress because no matter how a mattress “feels” in a showroom or it’s cost … it would have little value to you if the materials were lower quality and you end up losing the comfort and/or support that was the reason you bought the mattress in the first place much too quickly.
You can also read a little more about edge support for foam mattresses in post #33 here and post #3 here. In most cases it’s not a significant issue if the support layers are firm enough for your body type and sleeping style but if you do sleep with more of your weight concentrated on the outside edges of a mattress then it may be more of an issue for some people. I would make sure that any edge support isn’t “masking” support or comfort layers that are too soft for you because this can also cause “roll together” in the middle of the mattress where there isn’t any edge support.
In addition to careful and objective testing for PPP … I would make sure that you know all the information in this article about any mattress you are considering and if you list them on the forum I’d also be happy to make some comments about the quality of the materials or the mattress as a whole or help you identify any potential weak links in any of your “finalists”.
Once again … I would make sure you know the quality of the materials before you buy anything (particularly the Spa Sensations which uses lower quality memory foam) but many of the online suppliers listed in the tutorial post also have great return policies.
The most important part of the “value” of a mattress purchase is to make sure that it’s a good match for you in terms of PPP and the only way to know this is either your own personal testing or if that’s not possible then more detailed conversations on the phone with an online manufacturer or retailer will give you the best chance of success (see mattress firmness/comfort levels in post #2 here). No matter what the cost of a mattress … if it’s not a good match for you then it would have little value to you if you don’t sleep well on it.
Assuming that you are confident that a mattress is a good match for you in terms of PPP … then the next most important part of the value of a mattress purchase is to make sure that the materials inside it are durable and suitable for your body weight. No matter how well a mattress feels and performs in terms of PPP … if it loses the comfort and support too quickly relative to the price you paid … it would also have little value to you. Higher quality materials will last longer and maintain their initial properties longer before you cross the threshold between sleeping well on a mattress and just “tolerating” it.
After these … then the other parts of the “value” of a mattress purchase would depend on the other parts of your personal value equation that are most important to you (including cost of course).
Based on the stores you are mentioning I’m assuming that you are in the Denver area so you’ve probably seen the Denver list but just in case you haven’t then better options or possibilities I’m aware of are listed in post #2 here.
The tutorial post includes links to the better online options that I would consider if you are also open to an online purchase.
Buying a base mattress and then adding a topper can have some advantages because you can customize the comfort layer/topper based on thickness and softness and it allows you to replace just the topper instead of the whole mattress when it softens or breaks down faster than the mattress itself (which will usually be the case because a sleeping system will tend to soften or break down from the top down) but there are also more variables and additional risks involved when you can’t test the combination in person because you would have to make a “best judgement” choice about which topper will work best for you on your mattress and just like buying a mattress you may not always end up making the most suitable choice.
It’s usually “safer” to buy a mattress or a mattress/topper combination that you have tested in person and where you are confident that it’s a good match for you but this would also depend on the options you have available after you purchase a topper to exchange or return it if you make a choice that isn’t ideal in combination with your specific mattress. A topper that works well on one mattress may not work nearly as well on a different mattress. If you do decide to go in this direction then I would start with just the mattress itself and use your actual sleeping experience as a reference point to help you choose the topper that you believe would be best for you based on the topper guidelines in post #2 here and the posts it links to.
There are many variables that affect the sleeping temperature of a mattress besides just the materials in the upper layers of a mattress including your sheets and bedding but in general the newer generation of memory foams (gel or non gel) tend to be a little cooler than the slower responding and more temperature sensitive “older style” memory foam variants because they are less temperature sensitive, faster responding, and more breathable. There is more about the different factors that can effect sleeping temperature in post #2 here and I would keep in mind that all of them work together to either enhance or offset each other.
Phoenix