Set "total" timing on a stock 318 two-barrel where?

But mostly it sets the T-port sync, so you have a nice smooth transition from idle to part throttle. Too much idle-timing, and a reset to lower the rpm, tends to dry up the transfers and that causes flatspots and hesitations.
Since most people never floor the car at low rpms, not having the power timing cranked up down there, makes it easier to get it right at later rpms say from 2800 to 3600. Then you can install a big fast-acting Vcan and get the part-throttle power back where it needs to be.
Power timing on almost all typical pushrod engines is more or less the same; 34 to 38 degrees after about 3600rpm.
You are of course free to experiment; just be sure to stay out of detonation..