I got a small Z Lite and cut it down to six sections (the sections weigh an oz apiece, I'm 6'5" and broad enough that I can't cut it much narrower); just enough to cover shoulders to bum. I'm saving the extra four sections so I can combine the two pieces under my NeoAir pad in the winter, or extend the pad when the summer pack I'm using doesn't have any built in foam at all.
The accordion folding is fantastic because the dimples fold into each other, allowing it to fold much flatter than the comparable dimpled GG torso pad. It also allows the Z Lite to be unfolded once in the middle (provided you have an even number of sections, otherwise it will be uneven, which shouldn't be too hard to overcome) so it's half the thickness and twice the width, which with 6 sections makes it the perfect size and depth to go in my GG Murmur pack or Flash 50 to give it some support (tip: in a frameless pack, the height of your sleep/back pad will determine the "torso length" of the pack). The dimples allow better airflow back there when used in this configuration as well.
The foam hasn't suffered a bit from all this snipping, and though I might cut the whole thing narrower, I'm shying away from changing its overall rectangular shape, which I think would make it a less effective backpad for my murmer, which is how it's used the 2/3 of every day I'm awake.