I have a 6 string fretless bass, 34/35" scale, that I want to tune down to G# standard (G# C# F# B E A) for my prog band. So just two semi tones above your standard F# tuning, but I'm unsure of the string gauge, I've seen people say a .135 will do, and others say that a 166. Is needed. Anyone able to help me out? And also explain how and why the string gauges are what they are?