I just picked up a '72 Tele Custom RI. I am aware that the wide range humbucker in it is constructed differently than the originals. I've read about most of the boutique replacements too but they can get pricey. One thread l ran across mentioned modifying the RI pickups by removing the screw polepieces and the bar magnet and replacing them with magnetic slugs. I'd like to try this but l have no idea where to get the slugs or what size would work. Anyone have any suggestions?