I would set the initial with the vac gauge method then shorten the slots with the FBO $25 plate (fastest/easiest way to accomplish this) & get 31 total with mag/closed chamber heads and 35 with open chambered heads (initial+slots with can capped) then toss the heavy spring with the elongated loop on one end & sub in a Mr Gasket or MP light spring in lieu of it & keep the OE light spring for a good start. you want to stay just under the pinging point at WOT up thru the gears on your hottest/driest (most likely to ping) day. any ping you can hear is WAY too much and there is silent ping so you need a cushion (dont crowd the line too close). spring combo advances in a linear rate no matter what combo of heavy/light springs (after tossing the elongated slot one) you use so go lighter or heavier with either or both of em till you reach your goal and also you dont want the adv to start any less than 100-200 above your hot in gear idle speed which is what you will starting from when you pull away from the stoplight THEN plug in the can (if used) to ported & you want to stay just under the pinging point (same as before) in varying RPM/load conditions (everyday driving) on your hottest/driest day. CCW with a 3/32" allen wrench slows the curve amt added at a given in hg but not the total. EDIT found a chart, the crane kit is no longer available. I use the chart for the beginning of the curve possibilities not the RPM where they max. Every eng is different in dozens of parameters so proper max can be anywhere