I have Pachmyr pads on all of my rifles and shotguns, simple reason, if you're getting punished less, you'll shoot more and shoot better. Get a pad, take it to a good woodworker, put masking tape on the stock, saw off a piece of stock that is the thickness of the recoil pad so your length-of-pull and stock fit is not screwed up, make sure to cut the stock at the same angle or it won't fit well. Then have him mount the pad, etch the outline of the stock, then take it off and grind it down on a sander. One thing you can do to increase the effectiveness of the pad is taper the grind so that you fit the plastic to the stock, but leave the end that contacts your shoulder the same surface area, taper it on the sides. This will increase the area the recoil is spread out over, reducing the overall felt recoil. If you are good with a saw and grinder, do it yourself, but don't practice on your custom guns!
Selmer