Hi John2346 and new MUGster,
Welcome to the MattressUnderGround!
As stomach sleeper with a BMI of 28, most in your BMI class are going to prefer a firm mattress surface. I think you are on the right track with the 6" HQ HD36 35ILD and the transition layer using Dunlop 2" 29ILD. The HQ foam is a 2.8lb foam, which is great for higher BMI’s although the support factor under 2 could be an issue. I would have liked to have seen a support factor above a 2 in this instance. Depending on you actual height and weight, not just the BMI number.
My biggest concern here is the 1.5" of 4lb memory foam with an ILD of 14. This may prove to be a bit too plush and it may allow you to bottom out. With a larger mid section, sleeping on your stomach, this may cause a bit of dip in that mid section, hammocking you a bit and begin to strain your back muscles.
I imagine you are selecting ViscoElastic Memory foam for it’s pressure relieving properties and dont mind that warmer surface. This is a very soft foam and is not going to provide much secondary support. Remember, one bad layer choice can and will become a mattress’s weaking link, and will cause the mattress system to fail.
I am tempted to suggest a Talalay or even Dunlop mid ILD low to mid 20’s, 2" for your upper comfort layer. Perhaps even higher, or up the dunlop to a 32ish and then a talalay in the upper 20’s.
I know it seems like I am pushing you firmer, but stomach sleepers need that firm surface to keep that mid section from sinking. I would also recommend a quilted cover with a 50ILD foam quilted in.
No one can really tell you what you are going to be comfortable with. It is subjective as everyone is different. I am an advocate of going firmer and with the ability of swapping a comfort layer, or adding a topper to fine tune the system.
I imagine you want to keep all your layers ordered from a single supplier, and that may mean another layer of Dunlop, with it’s 29 ILD. 2 - 2 inch layers of dunlop with be softer than one 4" layer, as the support factor of 4" slap of dunlop is going to be higher than your HQ foam.
I would give it some thought, particularly on the memory foam comfort layer. I did not read through their very lengthy return policy, but if they would allow you to order your choice for set up along with an extra 2" dunlop, so you can make your comparison without having to wait for alternate choices and return the one you like least for a refund. That would be ideal.
Good luck with your project!
Maverick