Only vac adv changes rotor phasing from it's at rest with no vac position. Shifts it CCW on a SB around the clock the same number of degrees as the number stamped on the arm. Several ways to correct phasing, drill new roll pin hole(s) in the reluctor like Andy did way back or cut a new notch in the top shaft at the top where the rotor sets down into (may be other ways too). You want it slightly CW from dead center (rotor pointing dead on to the cap terminal center) then the can will shift it CCW & ideally you want the amount of distance from dead on centered to be equidistant on both sides (no vacuum and full vacuum). Then I'd set the initial with the "vac gauge method" then with that number in hand shorten the slots to get 35 total (initial+slots) and that is with vac adv capped then I would play with/adj springs THEN plug in/adj the can. timing and RPM do not change (rotor) phasing. I'd as SuperCuda said get the can on ported and get the idle speed down to a reasonable level (need enough initial timing first)