Hi Njones0100,
While I can certainly help with “how” to choose … I don’t 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” or PPP (Posture and alignment, Pressure relief, and your Personal preferences) 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).
Hopefully you’ve read the mattress shopping tutorial (which is the best place to start your research) but two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort” and PPP that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase 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 all the parts of your personal value equation that are most important to you.
While other people’s comments about the knowledge and service of a particular business can certainly be very helpful … I would also keep in mind that you are the only one that can feel what you feel on a mattress and I would be cautious about about using other people’s experiences or reviews on a mattress (either positive or negative) or review sites in general as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you and in many if not most cases they can be more misleading than helpful. A mattress that would be a perfect choice for one person or even a larger group of people may be completely unsuitable for someone else to sleep on (even if they are in a similar weight range). In other words … reviews in general won’t tell you much if anything about the suitability, quality, durability, or “value” of a mattress for any particular person (see post #13 here).
Having said that … the Ultimate Dreams 13" gel memory foam mattress certainly uses good quality materials and there are no lower quality materials or weak links in the mattress that would be a cause for concern in terms of the durability and useful life of the mattress but the only way to know for certain whether any mattress will be a good “match” for you will be based on either careful testing (hopefully using the testing guidelines in the tutorial) or your own actual sleeping experience once you have the chance to actually sleep on it.
If you are considering a DIY component mattress then I would read post #2 here and the posts it links to before making your layer or component purchases.
The thickness of a mattress or any individual layers inside it is really just a side effect of the design and the design goals of a mattress and is also only one of many variables that can affect the feel and performance of a mattress relative to any particular person and by itself isn’t particularly meaningful (see post #2 here). In some cases higher weight ranges will sometimes do better with a mattress that is thicker than lower weight ranges (see post #14 here for more about the effect of thickness) but even this depends more on the specific design and combination of materials in the mattress and on how well your testing or personal experience indicates the mattress “as a whole” matches your specific needs and preferences in terms of PPP than it does on just the thickness itself.
It would depend on the person and their weight and weight distribution, their sleeping style, and on their individual preferences and circumstances and on all the other layers and components in the mattress. Every layer and component in a mattress will have an effect on the feel and performance of every other layer and component above and below it and on the mattress “as a whole”. It would probably be softer than most people would use for a bottom layer but for some people it would be fine (again depending on the other layers and components) and for others it may be too soft. The only way to know how any combination of materials will work for you (regardless of how they work for anyone else) will be based on your own careful testing or your own personal experience.
Again there are too many variables to quantify this because it’s too subjective and will also depend on the specifics of the wool quilting and on the properties and specific type of materials (or memory foam) that are underneath it as well.
There is more about the pros and cons of a quilted cover vs a thinner more stretchy knit cover in post #12 here and the posts it links to. It would certainly be reasonable to expect that it would make a noticeable difference in how much heat reached the memory foam and and “affect” (not negate completely) the feel and contouring and performance of the memory foam but the only way to know whether the difference would be detrimental or beneficial for you would be based your own personal experience.
Regardless of how it would affect the feel or performance of the mattress … it would certainly help with temperature regulation.
Phoenix