I recently wound a full set of Strat pickups using 43 AWG. I also used 6mm
diameter alnico 5 slugs. The slugs are actually 2mm longer than the standard Fender slugs,so the pickups are slightly deeper. The results were really good. I made this set for my own use, to get a fuller sound, with less top end and and I'm very pleased with the sound clarity and much better bottom end and improved mids.
The specs. were as follows:
Bridge - 8000 turns, 7.22KDC, 2.31H,
Mid & Neck - 7600 turns, 7.00KDC, 2.22H
The wider slugs seem to give better coverage when bending strings.
The project was really experimental, but I have now made three more sets
to the same spec. to order, so, Hey, they can't be that bad!!