I've started making a comforter (duvet) with Momentum 90 and 800-fill down. It'll be similar to WM's Cloud Nine comforter. (Yes, the materials are awful fancy for home use, but the project is meant as an intro to MYOG with these materials)
I was hoping for some input of the largest advisable size for the sewn-through squares (or rectangles). 12"x12" seems do-able (based on some searching), but how much bigger can I go? Maybe 13x15? Does it depend on how much down I stuff into each square? WM uses 12 oz in their twin. I was thinking about using a bit more, perhaps 14 oz.
I plan on filling the squares individually, so fewer squares makes construction simpler. Advice?