when you use fabric softener sheets for paper (foundation) piecing you do not have to remove them- it stays in just like using any other foundation (besides paper) they are lightweight and the same as if you went to joannes and purchased lightweight sew in stablizer. the only difference is they have a smell now- and they are cut a certain size....same material. so you can use them if you want-
i use muslin most of the time for foundation piecing- because i don't like to take the time to remove papers- and don't mind the extra weight.