Hi there -- Thanks for your question. The answer to this is going to depend on a number of other factors, so there is no "best" that anyone can give you based on simply your weight and "firm" preference alone. That said, we have recently reviewed 2 mattresses that are explicitly designed for heavier people that could be a good match in your case. Once those reviews are published, you'll be able to find them here:

• WinkBed Plus
• Helix Nightfall

We also recently completed a review of another mattress that is not expressly designed for heavier people but that I think meets the criteria you outlined and that we did specifically flag as being a good option for many heavier folks:

• Brentwood Home Cedar

Also, if you happen to be in Southern California (AFAIK, the only region where it's available so far), there is a good local option with latex over pocketed coils that is designed for plus-size sleepers with a range of softness levels (ranging from Extra Firm to Medium). We provided an overview of it that you can see here:

• King Koil World Extended Life collection

If you are looking for a tiny bit of memory feel, another option that I think can be a good option for heavier people would be this one:

• Sapira

Lastly, there is one other mattress designed for plus-sized sleepers that is on our list to review but that we have not yet gotten around to:

• Big Fig

I hope that's helpful!