For a given low temperature, do you want more insulation in the underquilt or in the top quilt?

For example, I made a top quilt using Momentum and Climashield Combat and it will keep me warm into the upper 50's(sleeping in a tent w/a Big Agnes insulated pad).

Now that I'm moving to a hammock, what can I expect to need for my underquilt(alone - no pad)? Can I us the same thickness Climashield or will I need more under me? Or less?

I realize this is pretty subjective, but let's here some opinions and educated guesses.

Thanks - Jerry