Hi joshhp.
You may find some of what you’re looking for in terms of how ILDs and feel can different between foams in this thread and this thread
If you’re look at, for example, a 24ILD latex and a 24ILD memory foam, you’re going to find that the natural qualities of latex are going to be firmer and bouncier than a memory foam at the same ILD.
Alternatively, polyfoam (when made with durable material) maintains constant support and does not get softer when warmer (unlike memory foam - latex also doesn’t collapse under body heat). So, polyfoam will also provide a firmer sleeping experience (generally speaking).
NikkiTMU