Jon, I have the 9/32nds, but the holes are 1/4". I don't know if there are any geared pegs with 1/4 inch holes--and with shafts a quarter inch longer.
McGrath, I followed that link, too. I haven't had a chance to check the place out completely, but it has a good clawhammer banjo newsgroup to which I might post my question. I might also send it to Michael Holmes (Mugwumps.com), from whom I bought the Slingerland/Fawley. I did send him an e-mail when I bought the Stewart, but he never responded (I didn't ask him these questions)--although he responded to several messages before and just after I bought the S/F from him.
And Rick, I fully intend to upgrade the banjo some way, but I pause at taking a chance on messing up the neck by in the manner I described. I called Elderly's repair department and asked a luthier about it, and he suggested I go ahead with it (he would, because he can trust his workmanship--I'm not so sure I can trust mine). In preparation for doing the job, I bought a 9/32nds drill and a 5/8ths wood drill, but I don't have a drill press to make sure my holes are perfectly perpendicular to the headstock's surfaces,and I'm not sure of how to drill the countersink holes to the exact same depth (I'm thinking 3/16ths"). Is there some kind of stop you can attach to a drill to keep it from going too deep, one that won't scratch the surface around the hole?
--seed (and Happy Thanksgiving to you and Duckboots, too--and to all of you)