I just finished another motor conversion.
I have done two others using the arced mags and skewed arc mags but there was always room for more magnet material.
After turning the rotor and measuring, it seemed that 1/2 x 1/2 x 1/4 inch squares would fit.
Seeing other people use the round disks and having so much wasted space between the disks, I opted for the squares.
The offset for decogging is 5/16 inch. This is the distance from one tooth of the stator to the other.
I made some 'first row' jigs to keep the mags aligned until the JB KWIK set.

The second and third rows were more challenging to keep in place so I made some 'flux concentrators'.
They are 3/16 steel plate with a notch cut to accept the mags.

This made attaching and aligning the mags much easier.

After cleaning up the mags I covered them with a layer of fiberglass and resin.
There are 15 mags per pole for a total of 60.

The results:
No cogging
Cut in at 200 RPM Jerry rigged
9.5 Amps @ 400 RPM into battery bank @13.1 V
Not bad for a 3/4 horse.
This is just too much fun!
Bonz