I usually will straighten like Ube does but will rip fabric if I'm doing borders on the lenght of grain and especially on fairly wide borders--but allow for about an 1" to trim off. I also prefer that the fabric stores rip my wide back IF they do it right--which means doing a short cut and then very slowly and carefully (not pulling it all at one time)rip from the short cut outward--so that I get a fairly straight piece of fabric to straighten at home
