I am having covers made for the Fiero Seats in a leather-ette (vinyl) material, and can get bulk matching material with the order. By my measure my flat panel need is 8 2/3 yards of material 54" wide, allowing for panel overlaps, etc. I am thinking that it is prudent to order ten yards to allow for seam allowances, etc, but having zero experience and no design in mind I'm looking for some advice. I would rather have a yard left over than be 6" short, but I really don't want to throw money away on material that won't be used. What is a prudent waste allowance on yard good material?