There is zero reason to lock out a distributor, even in a drag car. If you need full timing to get the engine to idle you have other issues.

If you are going to lock it out, you need to get the engine to whatever the highest RPM the engine sees and set the timing there. If you set the timing at idle you won’t have a clue what the timing is at max RPM. Or anywhere else in the power curve.

That’s the ONLY away to set the timing on a locked out distributor.

IMO it’s bad tuning to lock out a distributor.