My most recent version of my DIY pack didn't use any CCF in the shoulder pads. Instead, I took a layer of 3d OCF and sewed it to a layer of breathable Cordura.
Took the whole thing, turned it over on itself with the Cordura on the outside, and sewed a French seam 2/3 of the way around the remaining edge. Flipped it inside out and finished the end with grosgrain edging.
It's a more traditional pack, in that the weight is supposed to sit on a waist belt rather than the shoulder straps, so keep that in mind. That being said, I've got about forty miles on it so far, and it's comfortable with up to about fifteen pounds (about what I'm comfy with on a store-bought pack) without using the waist belt for weight transfer.
The 3d mesh isn't all that much lighter than a fabric tube filled with CCF, though. It just breathes a lot better (a definite plus down here in FL 7+ months out of the year). I still sweat into the straps when the temps are above 50 F, but it helps a bit in keeping "soaked shirt" syndrome to a minimum.