I am trying to create a full collar on a man’s western McClure vest. I am making the front and back of the vest from a wool plaid and lining it with a different grade and color of wool. I am starting with Simplicity pattern #4762 view D. But the collar on that pattern stops at the shoulder seams. I want to continue the collar all around the back so it’s a complete collar. Do I create a pattern for the back similar to a facing and continue it from the front collar piece (meaning contoured like a facing)or should it be designed straight. I have very little pattern making experience and have myself stumped. Thanks for any help.