Tartan, did you see the recent tip that Patrick Lose mentioned when he was on F&P Love of Quilting on PBS?? He has a way of removing a bit of the bulk from corners which gives flatter corners. I was surprised to see that it actually worked. I have been hand sewing 1.75" double fold binding on mug rugs and it made a BIG difference with getting the corners folded. I have the same tape set up on my Bernina, only difference is my painter's tape is bright blue.