Hello all, So my addiction of doing this DIY stuff has gotten me 12 hammocks, 4 tarps, 2 climashield top quilts, a pillow hat, and many stuff sacks and things like that. i have a winter underquilt that i ordered the shell from underquilts.com and absolutely love it. the thing is, I stuffed it with a ton of down and its only good below around 30 degrees. ive decided that i am going to make a new underquilt starting from scratch. The goal is to be able to reach down to 20 degrees. my question is how much larger does the outer shell need to be vs. the inner shell? my plan for the inside shell is 48" x 66". ive read alot of differing opinions about how to do the differential cut and how to measure it out. Does the outer shell fabric need to be wider as well as longer? Ive looked for some plans and cant find exactly what im looking for. i ordered the fabric from dutch and am hoping to get started sewing soon. Thanks for your help!
P.S. i plan on using 2.5 inch baffles if that changes things.