Just how important iis the placement of canti bosses? Do the adjustability of the brakes alow for some lee-way? How far from the axel should they be placed for a 700c wheel? I'm just practicing Tig welding with some old steel junkyard frames.
Newer designs like the Paul don't have much vertical adjustment, so it pays to get the height right, and the centers. It is best to have the stuff you are building for before you build, though most people do it in reverse order.