Here is my prototype:
The second pic is just a close-up of the duct taped holes I used to attach the wings to the main body.
Without the duct tape, the pad rips very easily. With the duct tape reinforcing the holes, it is very difficult, but not impossible, to rip the holes by pulling on the connecting rope.
When I put it in my parachute hammock, it worked great; the wings overlapped each other at my hips, eliminating any gaps between them. However, the part of the main pad from my knees to my feet tended to roll up in a hump and needed to be straightened.
This was made out of the Wal-Mart $6 20" blue pads. It worked well in my parachute hammock, but my Clark has not yet been delivered (it is suppose to be here by 7 pm tonight).
I might make the final version from the Wal-Mart egg create type CFC camping pads (I think they are about $11 each), and lower the wings to leave some room for my head.