Ok, thanks for the advise everyone. For starters, it will just be a rectangular quilt. I may add omni tape at the bottom to make a footbox if I need to after this coming shakedown hike. I will try to take pictures, and if it all work out right I will send them to you HE. TeeDee, that is they way I saw it done on the internet, and I figured that would be more difficult for me. I don't have a very large area to work with, and trying to keep 3-4 layers of insulation and 2 layers of DWR in place while I sew would be too difficult. The pillowcase idea would keep the insulation trapped in place while I sew. Besides, that way has been done. I haven't seen this way on the internet, so I want to see how it works. That way people like HE and others can post it on their pages as another way to make a quilt.
My shakedown hike is next weekend, so this quilt will be finished by the end of this weekend. I will be sure to give a more detailed post on it's construction if it all works out. Thanks again.