Thanks to everyone for the responses.
PJ - I went ahead and ordered the ones I had linked previously, assuming that I can make them fit if I need to. However, I will send a short note to Parts Connexion and suggest the additions. It seems strange to not have them listed, when it seems that all the RCA jacks have their mounting hole sizes listed.
Howard - I found the information you did, after some digging. However, that only seems to tell part of the story. What we really need is the shoulder diameter on the washer, rather than the screw size. Of course, it's simple to make a reasonable guesstimate, and, if all else fails, it only makes me happier to get to fabricate something to make them fit!
I'll be sure and post here about fitment, when I get the posts in. Thanks again, guys!