Hey rvneedssleep,
Thanks for the post, this is always an interesting topic. As @diynaturalbedding explains, these ILD estimates are in a range. A key question with the toppers is what is the density of the toppers you purchased. Every Dunlop manufacturer sells latex by density, this is the specification they actually measure for every core. They do not test every core for ILD, really only Talalay Global, and Radium test every latex core for ILD testing. The most common densities for Dunlop manufacturers are 65, 75, and 85 Kg per meter cubed. Some have 70 and 80.
Additionally, the ILD of different materials or different types and blends of latex also aren’t always directly comparable to each other (see post #6 here ) partly because ILD can be measured in different ways and partly because ILD isn’t the only factor that affects the softness or firmness of a material so again using the ILD or other specifications of a particular layer as a reliable indication of how any mattress will “feel” or how firm it will feel to you compared to another mattress with a different combination of layers can sometimes be more misleading than helpful.
That said, as you keep the purchases from the same company, SOL, your chances of getting a feel “in the middle” of the two toppers is much better. If you choose a different suppliers latex from a different manufacturer, you may have a more difficult time getting the right feel.
Thanks,
Sensei