I did this same repair with my H16. I used the Hobie nylon inserts, which requires you to drill the hole out to 7/16". It's not 100% critical that they be drilled squarely, but of course, perfect is always a good goal. I just clamped my castings in a vise and hand drilled the holes. It worked good and really tightened up the slop. The mounts on the boat should be stainless steel, so the aluminum rudder pins shouldn't of worn them at all. Get the bushings and some new pins and you'll be in good shape for very little money.

Jack
Fort Loramie, Ohio