So, you’ve got your big lumpy cam and the accompanying super low vacuum, low gears, and a high stall converter.
You keep bumping up the initial timing and discover the vacuum goes up, throttle response gets better, idle circuit in the carb becomes more responsive.
You bump up the initial more, and get more of the same improvements.

As Chip said, if the combo is “wild” enough, you keep bumping up the initial, and limiting the sweep to keep the total where you want it....... and eventually you find there is no sweep anymore.

That’s how I came to it over 30 years ago........by making adjustments, driving the car and seeing if it ran/drove better or not.
More initial did everything better....... so I kept sneaking up on it....... more driving, more evaluating....... until there was essentially no “curve” left.
For the last curve I was at 30 initial/36 total, all in by 2200.
I locked out another distributor, swapped it out...... and it was marginally better, so I left it like that.