I'll let the Jacks handle this one as a final word, but with my Rag Mtn. I found that I needed to JUST be able to feel the TOP of the lofted "poofy" sections between the baffles when I stuck my hand between the hammock and quilt. I think this insures no compression. It's a bit different than a synthetic, because the down is so easily compressible.
I don't know that you have much of an issue there, though - many people say that 2" loft (like the Nest) only gets them down to around 30*.
"Physics is the only true science. All else is stamp collecting." - J. J. Thompson