Looking to do this with my Bartolini M3 & Audere 3ZB, loaded bass. Currently the PU's are just wired for straight humbucker ... so, I'm looking for a bit more tonal variety out of them. My fall back is to do the regular single coil/series/parallel switch, however I'd like to have a bit more flexibility out of my single coil option. So before I go and have extra holes drilled, and the cost of the work ... I'm just trying to get some feedback first. The idea of a inner coil/series HB/outer coil tap switch for each PU seems pretty cool ... wondering if anyone has this set-up. If so, how do you like it? Thanks & Cheers!