Rich, the easy answer is to pick up another set of 20 guage damascus 0 frame barrels and have them pimped up and fitted. A rotted bore set would work since these would be just used for shooting, add sleeve and choke tubes. You already have the solution to the pad issue solved. Mount the new one, don't cut the wood and keep the old one for resale. Let me know if you run across a set of tired 16 gauge 0 frame Dam while looking for the 20s, I have a similar project ongoing....
