I just ordered 2 sheets of foam, one piece 72"x40"x1/4" and the other 72"x40"x3/8" minicell foam, from these guys http://www.closedcellfoams.com/minicel.html
and got it a few days ago. I also picked up a cheap hotknife. I had hoped to create two pads with wings for shoulders and hips, and have the option to layer them together or use them separately for insulation. Brandon suggests this as an option on the WBBB site. I have a 1.1 dbl WB (god I love that thing), and hope to put pads in between layers.
What I'm looking for is guidance in shape and sizing for minimum weight, maximum coverage and what comfort can be achieved. I've seen a ton of good ideas in various parts, but no real 'best' shape.
I was thinking a coffin shape with wings for side coverage.