Looks like the coils for the littel 6.625" dual rotor will be round. 2.5" diameter with slightly less then 1.5" hole to match the magnets. I wound 6 of these coils for the 8 magnets per rotor.
100 turns of #20 wire at .25" coil thickness. The 2.5" outer coil diameter is all I could make within the 8each of the 1.5" magnets glued to the 6.625" steel discs.
Might not be optimum but I think it will work?
I'll start the stator part tommorow.
JK TAS Jerry