Hi Stormn,
As you can see from the steps in post #1 here … the step before finding the best mattress is to find the best manufacturers or retailers which can be one of the most important steps of all.
Both Denver Mattress and Rocky Mountain are good options and of course Rocky Mountain is one of the members here which means that I think very highly of their quality and value and their ability to help their customers make the best possible choices with an online purchase which can be more risky than a local purchase where you can test mattresses for PPP (Pressure relief, Posture and alignment, and Pressure relief) in person.
If you let me know your zip or city I’d be happy to let you know of any other possibilities in your area which may also be worthwhile including in your research.
There are some general guidelines about different types of construction here, along with some height/weight guidelines here and some sleeping positions guidelines here but these are meant more as general guidelines which can help you ask better questions and help you have more meaningful discussions with either local or online manufacturers or retailers. The people who either make or sell a mattress have (or at least should have) much more detailed knowledge of all the layers and components of the specific mattresses that they make or sell and they also have a large customer base that can act as a reference point for their customers so if the people you are dealing with have the knowledge and experience that makes them one of the “better” choices … then they are in a much better position to make specific suggestions for your needs and preferences than any “theory at a distance” which can’t take into account all the interacting variables of each person and all the details of the components, layers, and options that they provide. This kind of knowledge and guidance is certainly available at Rocky Mountain (and the other members here). At Denver mattress it would depend on the employee you are dealing with because with the larger factory direct manufacturers, not every outlet or employee has the same level of knowledge and experience.
With a bad back (and higher weight) … then the deeper support of a mattress (which is the most important part of alignment) can be more important to prevent the heavier hips and pelvis from sinking down too far. Firmer support is usually helpful and then the comfort layers need to be just thick and soft enough to accommodate your need for pressure relief in all your sleeping positions, to “isolate” your more sensitive pressure points from the firmness of the support layers, and to “fill in the gaps” in your sleeping profile (secondary support). The goal is always the best combination between the two “conflicting needs” of comfort (pressure relief) which requires softness and support (alignment) which requires firmness … in all your sleeping positions.
Comfort and pressure relief is easier to test for because it is more obvious (it’s what most people feel when they first lie on a mattress or go to bed at night) but support and alignment can be a little more difficult to test for and is what you will tend to feel more when you get up in the morning. There are some suggestions that can help you test for support in post #11 here. If you have good pressure relief and alignment in all your sleeping positions … then everything else is preference (and you can see a summary of many of these preferences which can help you decide which may be more important parts of your “value equation” in post #2 here).
Hope this helps.
Phoenix