4 off 6 mm on one car with countersunk heads (for a nice tidy look only) and 4 off 8 mm plain Allen head grub screws on the next car then 6 off 8 mm plain Allen head grubs on a third and fourth car. Three were done on a drill press_flywheel out. The first was done through the starter hole, counting teeth to keep it balanced.
Lengths all the exact width of the ring gear to just bottom on the flywheel ledge.
SAJ in NZ