Seems that, in this case, the quilting is more to keep the shell in place than the insulation. Thanks for the tip.
I'm considering making the quilt taper at the bottom to reduce weight. Anyone have any experience with a quilt made like that? My bed sheet mock-up seems okay, but I'm not yet fully confident in its coverage.
My only real problem with this quilt is that I won't have time to finish it before classes start and I doubt I can take my mom's sewing machine on campus (she would kill me). I'll have to wait until winter break . Oh well, more time to design it.