Hi mykvr6,
The thickness of higher quality foams (as opposed to just the thickness of the mattress itself) can certainly make a difference with higher weights. The Aloe Alexis may be a little better choice in terms of performance and durability because with higher weights you will tend to “go through” a single layer of latex more and the performance and durability of the transition (middle) layers become more important. There is more about some of the differences between an all latex mattress and a latex/polyfoam hybrid (with the Aloe Alexis more in the middle in terms of the amount of latex) in post #2 here and the other post it links to.
I would also keep in mind that firmer foam will generally feel softer for people that are heavier than they would for someone who is lighter and doesn’t compress the layers as much.
Phoenix