If you're starting from the frame, and really want a "dedicated, long-distance tourer," I don't think any of those three make sense. You'd be better off selling/trading one, two, or all of them and picking up a dedicated touring frame from the 1980's. Especially if you want things like front low-rider racks, three+ water bottles (or even two, none of those bikes have more than one water bottle boss, right?), seat stay rack braze-ons, long chainstays, etc. Any of those frames, being on the sport-road side of things, would be fine for light touring or to p-clamp some racks to for a little while, but if you're going to build something up I'd start with the right frame.