Timing gurus. Recommended initial and total timing for a warmed ove 273 commando?

1 person can check total timing, rev the engine until it stops advancing.

To observe when it's all in, then you may need someone else to look at a tach.

Big cam, small engine = more initial. Maybe low to mid 20's.

Total timing is a rotten method to time a street driven car. Get initial set where the engine wants it, then worry about mechanical advance and total timing. Simple test, at idle, turn distributor a little counter clockwise, if engine picks up RPM, it wants the timing at idle. Reset your idle speed, do it again. You may end up with a potentially locked out situation.

Springs usually change the rate at which mechanical advance comes in, rarely does it limit the amount. There is usually a physical limiter in the distributor, slot length, bushings, etc.

If it's not pinging at 40 total , run it. Check the ceramic of the plug for speckling, that's a sign of detonation.