I am of the school that rips. Cutting borders that long usually doesn't turn out well. It is a good idea to carefully press and starch the fabric before ripping that long a piece as the tearing distorts the fabric. After it is ripped press it again. I worked for almost two years for a shop that did custom dressmaking and alterations. Straight of grain is a real deal breaker. If you ever owned a garment that just never hung right it is because it was not cut on the straight of grain. The only other thing you can do is pull a thread and carefully cut where the thread was removed from the fabric. Good luck.