I have acquired several poncho liners to make into UQ and TQ. I have several questions regarding the sewing of the UQ. 1. I plan on taking the time to save and reuse the nylon edging, has anyone else done this? 2).Since 90% of my camping will be in the Sierra's temps are now in low 40s, will just a sewn poncho get me to that or do I need to add batting? I plan on using my 20 degree down bag as a top quilt. will both of these get me close to comfortable at 40 degrees? 3) Does an air gap between the inner and outer layer of the UQ help or should they be pretty much touching?