I've been experimenting with a few different cuts to trim some of the excess canvas away before folding the corners. Basically, I cut at a 45 degree angle from the inside corner to the outside corner of the stretcher. I open up the canvas and then make a cut perpendicular to the edge of the canvas, straight to the previous outside cut. It works pretty well, but I'm wondering if there's a better cut. It's basically two cut. I've seen videos where there are three or four cuts, but unfortunately, the videos are never clear enough to tell where the actual cuts are. Has anyone seen any very clear videos on trimming the canvas on the corners?