I always cut my binding 2.25" which is the standard when hand sewing to the back. 2.5" is usually what is used when you machine the binding down on the front. You might also look at Jenny of MSQC newer binding video. It has you stop a 1/4" of an inch from the edge and at a 45 degree angle, sew to the corner. You will get much neater corners. As Patrick Lose showed twice on F&P Love of Quilting TV show, I nip off just a bit of the dog ear which is excess bulk. Also make sure your fold on the back is the opposite of the front. It will even out the bulk of the corner. Judges do like to focus in on your binding. Here is a photo and if you look carefully, you will see the fold direction is different from the front on the back. This binding I cut at 1.75" double fold.