I've heard 600xBB for cash and 20 x buy in for STT
Don't forget to keep good records, I know I should

I agree on cash, I hold more like 30 buy in's for STT. I would like to know if this is regarded as excessive.
Important point....find a game that suits you and work at it.
With regard to moving up....keep accurate and detailed records of hourly win rates and play at your buyin for long enough to be confident that you are not dealing with short term variance. How long that is, I haven't heard a totally convincing argument of.