LA Mopar electronic distributor retaining clip

When do you determine when to eliminate vacuum advance
Drag racing. Its one more thing you don't need as it doesn't do anything at WOT and cool off and part throttle economy are not needed.
Hot rodders sometimes skip it because its easier not to use it.

Starting at the bottom right of the page is a good basic explanatoin of why centrifical advance is needed. And on the next page is vacuum advance.
Ignition System Analysis (Session 259) from the Master Technician's Service Conference

In my opinion, your engine should not need that much initial timing. Something in the range of 8 to 16*, 650 to 750 rpm would be more like it.
Here's a chart Barry Grant used to have posted for ballpark starting points.
Distributor starting point for a curve

Agree 32 - 34* should be about the max. for initial plus mechanical.
Around 50* for initial plus mechanical plus vacuum under highway cruising conditions.