I have to admit that contemplating mechanical advantage and straddle cable length always make my brain hurt so here is some advice from Sheldon. I will add that I've always found a cable adjuster somewhere along the track is essential to get the best out of a set of anti brakes.
https://www.sheldonbrown.com/canti-trad.html
https://www.sheldonbrown.com/cantilever-geometry.html
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N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '95 Gios Compact Pro, '95 Carrera Zeus, ‘81 Masi Gran Criterium, ‘81 Merckx Pro, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘VO Randonneur, Ritchey Breakaway Steel, Rivendell Rambouillet, Heron Randonneur, ‘92 Ciöcc Columbus EL