Hi Bazinga,
The specs for the Pure Latex Bliss Ultimate collection are listed in post #2 here.
The specs for Savvy Rest are a little more uncertain because they don’t provide exact specs but their general range are in post #2 here (although they may be slightly different since they have changed their Talalay supplier since that time).
I would also keep in mind that the type and blend and thickness of the latex layers and the specifics of the cover and quilting materials can also affect the feel and performance of a mattress and how soft or firm it feels so going by ILD alone may not be a completely reliable way to “match” one mattress to another one although it can give you a general reference point.
Phoenix