I agree that "single multi-coils" (one coil per string) work very well. All the multi-coils I've built have been that configuration; one coil per string. Alternate wind/alternate magnets to make the group humbucking. I made my coils long ovals along the line of the string to get more wire in, and surround three round magnets each. For power and output, because I made mine to run passive only.