Question regarding foam filler for Latex Hybrid DIY

Hi everyone… I ordered some components originally from Arizona Premium Mattress for a DIY build… Originally, from bottom to top - I was using the Quantum Edge Elite Bolsa, followed by 2" natural talalay medium (25-29 ILD), and 3" natural talalay plush (20-24). This ended up being a bit soft for us, so I swapped out the 3" talalay plush with a 2" dunlop medium topper from SleepOnLatex… We’ve been pretty happy with this configuration so far, but the bamboo wool cover we originally ordered was 13", and now is a little loose.

I’d like to order a 1" piece of foam just to fill the space in the cover… What is the best foam to use for this purpose, and where would be the best place for it where it wont impact the current feel and heat retention? Would a 1.8 lb/ft3 density, 35 ILD HD foam be sufficient for this purpose, placed either below the pocket coils or as the 1st layer on top of the coils, before the latex toppers be sufficient for this purpose? Or would I be better off with something more dense like a 2.8 lb/ft3, 35ILD?


If you are worried about the cover being loose I would just order a 1" piece of firm foam from SOL and put it at the very bottom under the springs (so it won’t change your upper configuration at all.