So, it has occurred to me that probably the best way to get the gearing that I want on this bike, 45/42/granny half-step triple is to buy a nice, used 52/42/30 road triple, which are everywhere, and cheap, and mostly good looking, and a bottom bracket, and a 45T chainring in whatever BCD goes with whatever crankset I buy.
Converting the existing 110 double crankset to a triple requires 2 new oddball chainrings, a 45 and a 33, the extra-long chainring bolts that this whole thread was about, and a new bottom bracket spindle unless I get really lucky with the chainstays.
The rear derailleur is a 1980 Suntour Superbe, which I want to keep on the bike, since (1) it's a 1980 Suntour Superbe, (2) It's a Fuji and Fujis should have Suntours, (3) I had to take it out of the box and untwist the twist tie from the mounting bolt when I put it on the bike, and (4) I think I paid 15 bucks for it.
Specs are 23T max cog and 26T of chainwrap. On a Suntour dropout, it easily clears the 26, and I'm pretty sure a 28 would be fine, so I'm thinking the specs were really, really conservative. 45/42/30 and a 14-26 is 27 teeth, so it should Just Work (tm).
There's even a neato gear phreak bonus: The really sweet thing about the 45/42/33 idea was that it's a half-step over 1.5-step, so you get 7% half-step gearing on the 42/45, with 2 full-step gears on the granny. So it's a simple double shift to the granny if you didn't anticipate the need. The 45/42/30 is a half-step over 2-step, so you get an 8% double-double shift to the granny, 42x26 to 30x20, and then two full 13-15% steps below that. And the low gear goes from ~34" to ~31", or one full step lower. Plus, the few duplicate gears are all on the granny and you'll almost never ride 'em.
Tl;Dr: If you want a triple, buy a triple, unless you wanna be wierd just 'cuz you can. Which is super cool and I support it.
--Shannon