How about either a Nervar Star or a Stronglight crankset as a period-correct, high-quality, good-looking, lower-priced alternative to Campagnolo? You could also "cheat" with a vintage Campag.-clone Sugino crankset.
As for the rear axle, I would vote for 130mm with your 6-speed freewheel. Stacking a bunch of spacers on the LEFT side of the axle would then enable you to reduce the rear wheel dish significantly.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069