Here's my pillow setup. Left to right, the components are the following: a 1.35 oz. Quixote fleece pillow case, which has also been used as a pot grabber and a food cozy; a 1.5 oz. GG SitLite pad, which is also my Jam back padding (I ditched the heavier stock frame sheet), which is also what I use when sitting on a log or rock; my BPL Cocoon pants (7.3 oz., size L), which I always carry but seldom need to use (except on chilly Rocky Mountain mornings).
First, I slip the SitLite into the pillow case, with the bumps facing inward,
Then I stuff the Cocoon inside,
Finally, I secure the 4 Velcro dots I'd sewn onto the pillow case to keep everything together. I end up with a nice, firm, comfy pillow, at a weight penalty of 1.35 oz. (if you don't count the multi-use of the pillow case).