I'm not sure what Turbo actually is, but if I recall correctly it is mostly just setup into U perms right?
Personally my methodology for 3BLD went like this: OP/OP -> M2/OP -> M2/Orozco -> full 3-style. I didn't find the transitioning from M2 to 3-style particularly more difficult than from Orozco to 3-style. I don't really see a point in using more in-between methods like Turbo or Eka. Because of that, I think it's better to just do r2 for 4BLD wings.
Btw, I've only used 3-style for 4BLD, 5BLD and 6BLD. My first 7BLD success was with r2/U2/OP, but that's because for no reason I did 7BLD before 4,5,6BLD.
Good luck learning bigBLD!