Hi skewerz,
When you are in higher weight ranges … there are two things that become more important.
One is that you will need firmer materials in both the comfort and support layers so that they don’t compress or sag under the heavier parts of your body as much so that the mattress is a good match for you in terms of PPP. Firmer materials will “feel” softer for those that are in higher weight ranges because you will sink into them more than lighter body types.
The second would be that you will need to focus on more durable materials and components that will hold up under the stress of your higher weight for a longer period of time.
Other than this … the type of mattress and materials you choose would be based on personal preferences because no matter which type of materials or components you prefer they will have softer/firmer versions and higher and lower quality versions.
There is more about some of the guidelines I would suggest for those that are in higher weight ranges in post #3 here and the posts it links to.
Other than these … I would follow the same steps in the tutorial post as anyone else regardless of your weight.
Phoenix