I've got GHS Precision Flats on an Epiphone Embassy PRO with T'bird pickups and it sounds great to me. I do use a VT Bass pedal with the mids boosted slightly.
Fender Bass VI set for 30" scale Fender Bass VI but, due to tremolo/vibrato tailpiece on Bass VI, the winding length ball end to silk is 35".
I doubt they would fit 34" scale bass.
I'm just a four string EADG bass guitarist so I am definitely a mere mortal but Bach is beautiful to listen to and I have always loved Red Mitchell.
Enjoy the reading.