I made two pair of pants in 21 wale corduroy for my granddaughter. One pair has nail polish up the front of the leg. I would like to cut off the legs and make shorts. Do I measure the same amount of inches from both the bottom hem up the inseam and up the outer seam or do I measure from the waist down on the outside seam and then not sure how to measure the inseam at that point? Is there a trick to getting the hem straight on shorts?