On a side note, holy resurrected thread Batman.
Kind of a damned-if-you-do-damned-if-you-don't kind of thing. I searched and found this thread which looks like it provides my answer but I wanted to see if anyone knew for sure that this setup would work, and whether anyone had an exploded view. Looking up-thread, I think I do have a good combination of shifter and derailleur since the catalog shows my bike to have an RDL-525 S.I.S. and T-Mar says the 424 works with an "RD-L525" which I assume is the same thing.
The shifters fit on the bike fine; I haven't done the cabling yet though. Before I try to get everything working I'm going to clean it all up first before I put everything together for good.