Lead shift ,Rewinding 24 bar 12 slot armature

I am rewinding an armature for an old-model metal-bodied Chinese mini angle grinder (approx. 700W-850W, 11,000-12,000 RPM).

Technical Specs:

- Core: 12 slots, 24 commutator bars.

- Dimensions: Core length 55mm, diameter 3.2cm.

- Wire: 32 AWG (0.20mm).

- Winding: Factory was 22 turns/coil (88 wires/slot total), but I plan to use 23 turns/coil (92 wires/slot) to improve torque and heat management.

- Pitch: 1 to 6.

- Progression: Retrogressive (1 -> 24 -> 23).

- Brushes: Positioned 90 degrees from the stator coils.

- Potting: Using two-part submersible pump epoxy (thinned with heat) in a vertical gravity-pour method.

The specific question is about the Lead Shift:

Because I am adding an extra turn (23 instead of 22) and the brushes are at 90 degrees, which lead shift is best to handle the high RPM and field twist?

1. Zero Shift (Bar 1 directly in center of Slot 1).

2. 7.5 Degree Shift (Mica directly in center of Slot 1).

3. 15 Degree Shift (Bar 24, one bar left, in center of Slot 1).

I am leaning toward the 7.5° (Mica Center) shift as a balance, but I'm worried about "fire-ringing" at 11,000 RPM. Has anyone done this specific 23-turn mod on these 12/24 armatures?

By ibot guess, the magnetic shift will ne around 18degree. I can't retrieve any original data of lead shift but from one saved coil, i get continuity from bar24 and 23, assuming first bar in center of slot is bar 1 and winding is retrogressive, connections moving left.