This is off the exact subject of your post, but I have been buying three packs of disposab;e cookie sheets, 12" x 18" overall. I cut the rolled edges off and fold them not more than once and lay them flat in the bottom fo my bag. If you lay a peice of kitchen twine in the crease, it prevents the folk from being sharp enough to fatigue the fold line, and the crease is over on the edge of my bag and out of the way. I have not had a problem with poking holes in them because all the gear in my bag is in soft containers (smooth and round).