fastest would be to set the initial to 15 then shorten the slots to get 36 total (can unplugged) then mix/match springs so you are just under the pinging point at WOT up thru the gears on your hottest/driest day (no matter what RPM that makes the slots max out at) then plug/adj the can (CCW makes it come in slower). that'd get you REAL close. You could set the initial with the vac gauge method then shorten the slots to get 36 total (initial+slots) and then the springs then the can. the slot length= so many degrees chart is around but if you can find it when you get your initial I'll find the slot length for you (to get 36) if you wanna weld/file the slots EDIT .412" will get you 21 from the slots. And you definitely want to toss the heavy spring with the elongated loop on one end