Hmmmmmmmm. I think I have all of them, but haven't looked at them in years. Mostly to check out colors, what was painted what or orientation on the originals. Night-stand dreaming material. I have a '59 TR-3A also, and unless you are totally anal about restoration to original (sounds like you're not) or are seeking a concourse competition, no need. I think if we had long-door TR-2s, that'd be different. I mean, there were tens of thousands of our cars produced... That being said, nothing I've done can't be reversed (electric fan, rack and pinion) by the next owner.
On the other hand, my Triumph Service Manual (a red hardbound book from the factory) is falling apart, torn, dirty, and greasy. But-- Absolutely the one book you want, or a reprint thereof. Very well written, too, in the King's English. Tells you the procedure to follow to do everything. Especially useful to have the Moss catalog page open to what you're working on at the time.
That being said, working on these cars is simple, but not easy. For example, the manual will tell you to remove the three so-and-so bolts-- simple enough to follow, but chances are that one of them will be frozen or will just shear off in your socket--i.e., the "not easy."
Between that manual, the TRF and Moss catalogs, and this forum, you don't need much else. Oh, and a checkbook. Best of luck!! Jim