I have the 54 Pro in the middle and it is so weak and thin compared to my Air Zone. I would personally go injectors or Fast Track middle. I really hate weak thin singles, I come from always using humbuckers so if I switch to a single or in between position, I tend to drop out of the mix cause my output and volume drops so much, especially being a hard rock or metal guy. I will only use powerful singles that can hang with humbuckers. I am going Chopper, Fast Track, and or Satch Track or Injectors. My 54 Pros would not keep up and neither would my Fender high output noiseless. So far my favorite single coil sized pickup is the Chopper and the Duncan Little 59. However, these don't sound much like single coils but under gain and clean, they will be cleaner than a typical humbucker and that is all I really want out of so gle coil sized pickups. I can't change my style. Even Hendrix, I always played on my LP Standard. Haha.