Working on sorta the same project but mine may be easier. I'm looking for a 22 inch 20 Ga gun or just the barrel but the more I think about it the more I would want choke tubes. I.C. for the rabbits, mod for early season squirrels and full for late season (no leaves). However, I don't need the drill and tap since I want the fast bead shot sight. Slugs will just have to be ranged in with the bead but if I could get 6 inches at 50 yds that would do since it would be primarily for shot and the slug would only be "deer if by chance" while small game hunting. My stocks would be my existing pallet wood already cut to straight, English style and thinned down some. My only thing missing is a good 20 ga barrel and possibly finding a screw in choke set-up. Good luck with yours.