For a hair-hide sporran (as opposed to fur), there is usually a distinct grain of the hair, and it tends to change directions as you move around the hide. I did a sporran from a customer-supplied deer hide, and I kept running into directional changes that are hard to see until the piece is cut out. It drove me nuts.

Probably the best location to cut the front panel from a hair hide is right down the center of the back, as the hair typically "parts" there and you have the best chance of good "hair symmetry".

Next, if you want a gusset from the hide, you really want two pieces each just over half the length needed for the gusset, because if you cut a full-length piece and sew it on the fron and rear panels, one side will have the hair running down and the other will have the hair running up. You cut two pieces and sew then together with the hair running toward the seam - the seam then is positiond at the center bottom.

hope this is helpful.