I feel like I tried every fly sheet available, including Amigos and Rambos, and everything rubbed on the point of her shoulders. (SmartPak hates me for the number of sheets that I returned to them.)
I finally tried Weatherbeeta’s “summer sheet,” which is half super light weight sheet and half mesh fly sheet. It has substantial padding at the withers that seems to keep the sheet from getting too tight at the shoulder. I was worried that it would be too warm, but it doesn’t seem to be any different from all mesh fly sheets. It also annoyingly only has a little “belt-like” attachment at the chest that comes completely off (i.e., easy to lose), but I’m willing to put up with those things to get a fit that doesn’t rub.