One more thing to mention, as someone who put 17s on my classic...
17+ inch rims that have large openings between the spokes will make it even more apparent how terrible stock brakes are. I had factory 4-piston power discs on mine and they look tiny, like the ones on a Honduh, where the rotors are visible. Drum brakes look even worse, even those giant Galaxy/F150/Shelby drumes look small inside a 17-inch rim.
Plan on some future 13-inch rotors and probably 11-12s in the back into your budget as cash flow allows.