Hi cbear08.
Based on the specs you provided the mattress you are considering has a few weak links for higher weight ranges. Please revisit the information I provided about selecting a mattress in thedurability guidelines here for BMI ranges higher than 30 section. I would place a caution on both the 1.8 lbs/ft[sup]3[/sup] polyfoam and the gel memory foam of 4 lbs/ft[sup]3[/sup]
Higher BMI ranges will need more durable materials and components in a mattress and in a BMI range of 30 or higher I would include any 1.8 lb polyfoam or 4 lb memory foam as a “lower quality/density” material (relative to a higher BMI only) and minimize their use to a total of “about an inch or so or less” in the mattress.
Polyurethane foam: If your mattress is one sided then I would look for 2.0 lb per cubic foot density or higher. If the mattress is two-sided then I would use a minimum density of 1.8 lbs per cubic foot or higher.
Memory foam (or gel memory foam): If your mattress is one sided then I would make sure that any memory foam is at least 5 lb per cubic foot. If the mattress is two-sided then I would use a minimum density of 4 lbs per cubic foot.
There are also a number of forum posts and threads about mattresses and higher weights and a forum title search on heavy (you can just click this) will bring up many of them. Some examples include post #2 here and post #2 here and this thread
Phoenix