Hi bitz424,
Yes … I would be looking at memory foam mattresses in the range of 5 - 8 lbs density and because of your stomach sleeping I would tend somewhat towards thinner layers that provide you with good alignment and pressure relief in all your sleeping positions (if you sleep in any other positions besides your stomach). 4-5" may work well for side sleeping or even back sleeping but for stomach sleeping thicker layers of memory foam may carry a risk of hammocking. This is also where 7-8 lb foam can play a role as part of the memory foam layering because it can be both softer and also more supportive (at least as much as any memory foam can be supportive).
I would also suggest careful testing on mattresses as objectively as possible (testing specifically for pressure relief, alignment, and how the mattress performs with movement) and preferably with the help of someone who has the experience and knowledge to help you make good choices.
While there are no factory directs right in Worcester, … there are two “clusters” that would involve a fairly short drive. East of you is listed in post #2 here and west of you is listed in post #4 here. There is some feedback about many of these in various threads linked in post #2 here.
If you are committed to memory foam or gel memory foam … I would take some time on their websites and talk to them on the phone to make sure they make or carry them because there may be some who don’t make memory foam mattresses.
Also … if you go east I would probably also consider dropping in to Boston Bed company in Framingham or Natick who carry some Therapedic mattresses that may also be of interest (depending on the mattress layering) and seem to have good value.
You are probably wise to cancel given the lower quality of some of the materials in the iComfort mattresses which would not likely do well with your weight.
While they aren’t right in your back yard … you do have some very good quality and value choices near you and some time on their websites along with a few phone calls and a visit to the ones that are most promising and carry what you want to test will likely save you a great deal of time and frustration compared to going store to store trying to sort through all the marketing information, dealing with people who don’t know a lot about mattress materials and construction … and sell mattresses with lower quality and value.
Hope this helps and if you have questions along the way feel free to post.
Phoenix