Hi Da,
That’s certainly a big jump in budget and I would also question spending that much on a mattress as well when there is only 1/2" of gel and the rest is polyurethane. There may also be other gel options available to you such as the Evosleep in this thread.
If it was me, I would want to know for sure that I couldn’t get to 90% using either different latex layering or even other materials before I went in that direction (or that budget) unless there as clearly nothing else that would do and the cost justified the benefits compared to any other mattress I tried (not just the PLB).
Phoenix