Hello, I am planning on experimenting with my own pickups. I bought some rod alnico5 magnets from mcmaster-carr. They are about 4" long and are polarized N in one end and S in the other. I never considered that I have to cut them, but I don't know what'll happen to the polarity or how that would affect the pickup. If I cut, say 1/2" off the N side, will this piece of magnet still work for pickups? thanks.