Risk and Chuck:
I tried a thermarest in a Speer hammock once, and
it did pretty well. But then, it was between two
layers of hammock fabric, and that kept it in
I've also had good luck with a Mountain Hardwear
Backcountry 60 pad in an HH. It's a combination
closed-cell and egg crate foam pad inside a cloth
envelope. The important feature is that the bottom
fabric is slippery while the top fabric is grippy.
So the pad stays put underneath me, but slides
around on the hammock okay. It seems to stay under
me as I move around. But it's narrow, so my
shoulders want a little something extra.
Back to the question though... I'd go with the
blue foam pad, especially if you cut it in half
for overlap or T use.