There are a LOT of vest makers - both leather, cotton and mesh out there. If yours will be yet another Made in China thing to sell at wally world, I will wish you well, but also tell you I will never buy it.
I want a QUALITY made vest, extra stitching at the critical points, and most importantly, MADE IN THE USA.
For sporting clays, and especially FITASC, the vest needs leather on the front where the gun will be mounted and it needs to be from the at least the waist, if not the top of the pocket, for the FITASC folks. If it can incorporate a pocket for one of the recoil reducers that skip inside, even better for most folks. A summer version needs to be as light and airy as possible for those of us who shoot in warm climates. You'll need a ring or two for towel and wad knocker, minimum of four pockets for shells, place for glasses, maybe a few loops for choke tubes and it needs to be priced below a house payment