I am going to make a poncho liner underquilt. I bought this Roc-Lon drapery insulation stuff at Jo-Ann's Fabrics that has multiple layers. Two of the layers are space blanket type material. One layer is Insul-Bright. I am not sure if these layers are breathable or not. Does the underquilt need to be breathable? If it does can I just punch a bunch of holes in the insulation before I sew it up in the poncho? Any help would be great.