In my opinion, the classes you want/need for 3* and 4* crafts:
  1. CUL 37 (required)
  2. CRP 50 (absolutely required)
  3. WVR 50 (possibly not required, but I consider it to be. My most used and loved skill of all time)
  4. ALC 50 (gives you +28-42 CP on high end synths - that's a lot of CP, essentially required for my 4* crafts and really handy for my 3*s)
  5. BSM 50 (major Progress/Quality buff for 3* ONLY - do NOT use in 4* crafts, where it has no effect)
  6. LTW 15 (very nice for 3* crafts only - I don't use it in 4* at all)
  7. ARM 15 (for 4* crafts only - rapid is pretty much required for any 4* rotation I've seen)
  8. ARM 50 (practically required for the Master Book II tokens, but only saves you one step on other 3* rotations, and I never use it on 4* rotations. Skippable... if you can get the books without it)
  9. GSM 50 (nice quality boost on your BB and great padding when fishing for Good/Excellent, but not required by any means)
  10. CUL 50 (nice for Master Book II turnins and little else)

I use this rotation for the Master books. It's very good, but requires 448 Craftsmanship, 390 CP, CUL 50, CRP 50, ALC 50, ARM 50, BSM 50, WVR 50, LTW 15, and really benefits from GSM 50. I don't know what I'd do for that rotation without ARM 50 or BSM 50...