I have a WBRR with a 1/8 foam pad in the pocket plus a JRB greylock UQ.
this works well but I am not sure why. It seems to me the combination of both should not work well together.
I think I might be missing something on how insulation works. I understand that I am the heat source putting the air into the down in the UQ which then traps that warm air.
If I then put a foam pad with an R value of say R2 or R3
between the heat source and the down of the UQ I will be blocking heat
from getting to the down to warm it up. The heat then has to radiate back
up through the R value of the pad.
I feel that the combination of both would be warmer but I don't know why.
It seems to me that if the foam pad was below the down it would be more efficient but hard to do. And then there would be a condensation problem
which is even more difficult to understand. Maybe open cell foam below
the down would work. Maybe the answer is forget the foam and go with more down. More down seems a good answer for all problems.