If you cannot get your back piece from one skin you will have to divide the measurement in half and use two but always starting from the neck area and working downward and across. The reason is in the stretch of the hide. It will stretch some from neck to the bottom but will stretch quite a bit from side to side. For arm fringe you will cut the outside of the arm piece wide enough to accommodate the fringe area and sew the seam with the fringe hanging on that side. Fringe is not just decoration, it wicks water from the leather if you are exposed to precipitation or accidently get wet.
Western dresses are usually one piece.
Eastern are usually a wrap skirt with a long overblouse. Shirts and legging styles also varying. If you are simply making utility clothing or reinactment outfits, just be sure you are not adding decorations that might mean something particular to another Nation's people. Be careful to measure your neck and divide by 4, as it is very easy to get the neck too large. Then cut a slit down from the center of the front neck edge just large enough to make an opening for your head.