Hi Carmen1229,
Welcome to the Mattress Forum! 
[quote]I have our next mattress narrowed down to the following:
Helix
Nest Bedding Latex Hybrid (not the signature hybrid)
Avocado Green Mattress
Oso
Do you have any words of wisdom on any of these mattresses?[/quote]
You can use the search feature of the forum to pull up information about the Helix, OSO and Nest Bedding Latex hybrid mattress, as I’ve written quite a bit about those already. I can also give you a brief synopsis here.
The Avocado Green Mattress hasn’t been mentioned here before on the forum. It uses 2" of 75 kg/m3 (plush) Dunlop and 1" of 95 kg/M3 (firm) Dunlop. The pillowtop version adds 2" of 85 kg/M3 (medium) Dunlop. It is 100% NR latex. It uses the Leggett and Platt Quantum Edge Bolsa Nested innerspring unit. This mattress features good quality and durable materials, and there would be no “weak links” in its componentry. The cover is wool and organic cotton. The only ability to customize is to add the pillowtop option. It has a 100 night sleep trial.
The Nest Bedding Hybrid Latex has a zippered top with a choice of 3" firm or medium Dunlop 100% NR latex, and can be split per side. It uses a 5 zone pocketed spring unit. It has wool and cotton in the upper quilt layer, with a 100 night sleep trial. There are all good quality and durable materials here and there are no weak links in the mattress relative to any weight range. This item is customizable and would be the closest in componentry to the Avocado, while offering a bit more flexibility in comfort preference.
The Helix and the OSO are in different categories from the Avocado and the Nest Bedding mattresses.
The Helix mattress uses a customizable combination of 3 different comfort/transition layers that includes 2" of Helix Dynamic Foam (HD polyfoam) in one of three different firmness levels, a 2.4" microcoil, and 2" of 1.8 lb polyfoam also in one of three different firmness levels. They use a questionnaire with their customers that takes information such as BMI, body measurements, and sleeping positions into account and use an algorithm to choose the order and firmness of each of the comfort layers that are most suitable for each of their customers. The 3 comfort layers are on top of 4" of 1.8 lb polyfoam with two different firmness levels. They can also build a side to side split with different combinations and firmness levels on each side of the mattress for couples with different needs and preferences. They use good quality materials that would be suitable for most weight ranges in terms of durability but I would add a caution for higher weight ranges (more than about the lower 200’s or so). There is a 100 night trial.
The Oso contains a 1.5" layer of blended Talalay latex on top of a 1.5" layer of 2.0 lb polyfoam as a transition layer and a 6" 2.0 lb polyfoam base layer. The base layer has a cutout under the shoulders and upper torso that contains 3" Reverie dreamcell cylinders which are made from 70% natural/30% synthetic latex which creates a softer zone under the shoulders and upper torso, or under your hips, depending upon which direction you sleep upon the mattress. These are all good quality and durable materials and there are no weak links in the mattress relative to any weight range. They have a 101 night trial.
Nest Bedding and Reverie (OSO mattress) are members of this site which means that I think very highly of them and that I believe that they compete well with the best in the industry in terms of their quality, value, service, knowledge, and transparency.
I think you’re already aware that all I can help with is “how” to choose, as 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).
I hope that information about each mattress is helpful. If you have other questions, please feel free to post back and I’ll do my best to answer them.
Phoenix