Hello RIO, I'm back! How have you all been doing? Crushing games I hope.

I've decided to get very serious about my MTT game recently (and am hoping to take my game literally as far as I'm capable of taking it), after I discovered I have a significantly higher ROI than I do in cash games (over a sample size of about 900 tournaments, in a field of 100-500 entrants), and I was wondering how many buy ins a professional (who has no other income other than poker) would use for their overall strategy. I've heard a number of examples from 100 BIs to 500 BIs, and I was wondering what the community on RIO think is the optimal number for MTTs. 

In addition to this, should you use a different bankroll management strategy for live MTTs, and if so, what would people suggest is the optimal amount? (I would imagine if it does differ, you would need fewer buy ins.) Thank you!