35 (initial+slots) is a very close to ideal SB amt & definitely a good number to start with & with a DD 318 you will be fine. I would set the initial with the "vac gauge method" (or 15-20 is fine) then shorten the slots with the FBO $22 plate (by far the best bang for the buck for this) to get 35 total (can capped) then toss the heavy spring with the elongated loop on one end & sub in a mr gasket or MP light spring in its place for a good start & go heavier on either one if it pings up thru the gears on your hottest/driest (most likely to ping) day (any spring combo advances in a linear rate ex for the OE elongated loop one) then plug in the can & adj it to stay under the pinging point in everyday driveing under varying load/RPM conditions (CCW slows its rate). bottom line NO pinging allowed ever but you want to stay fairly close to that line but NEVER over it. if you accell at a lower than WOT rate then plug in the can before the doing spring work/changes.