On the win rates:
I would expect a solid NL200 regular, who can successfully dumb down their game, can expect to win at least 5bb per hour at a standard 2/5 game or even 5/10 game after making the proper adjustments. That rate is considering a 100bb buyin in both. In the deeper games you would expect the win rate to go up. Over time I would expect it to go up. However, if I was planning on completely shifting from being an online professional to being a live professional player then I would probably cut that estimate in half and have enough bankroll to weather some decent break even periods.
With that said, no matter what you bankroll is I would absolutely start at 2/5 even if you play higher than 100NL. There will be an adjustment, to several things that are different between the games. First, getting used to how much slower it is, but if you can focus you can learn a ton about players much faster. Second, adjusting to all the limp/calling and limp/folding and the strange ranges that people have. Third, adjusting to the passivity (especially preflop), Bart's totally right the average non-professional players at 2/5 and 5/10 are probably around %30 vpip with a 5% pfr and a 2% 3bet (QQ+ I doubt even 50% 3bet AK). Four, adjusting to the instant money instead of it being a number in an online account you constantly have all this cash and know how much you win/lose in a given day, which can have big implications on tilt. Five, not tilting when you aren't winning in a game filled with some of the worst players you have seen.
Based on those thoughts and a few others, I would suggest a 20 bi minimum if it's not going to be your only source of income. You could tweak it down to less once you are used to live players and games. However, you have to remember it is easily possible even at a big win rate to go on a 200 to 300 hour break even stretch and if you are a professional player there are several more considerations for your bi requirements based on expected win rate. If it is going to be your sole source of income then I would actually suggest double that.
Most of the 5/10 games in Vegas are raked on time, usually 6 to 7 a down (every 30 minutes). Of the 2/5 games I believe that the Venetian still has the best rake but it also usually has the toughest games. I think the rake is $1 for every $20 in the pot with a max of $4 bucks (no bad beat jp drop).
In other locations, I could spend a few pages explaining the raking methodolgy. I think in most "legal games" the rake is almost always capped. However, in many underground games the rake often isn't capped.
For example, at one casino, they drop $1 every hand for the bad beat, and they pull the standard rake schedule if 1 player limps in, but if the blinds are stolen then only the $1 is taken. Of the standard drop, they take 10% of the pot up to $5. Based on this rake at 5/10, the table pulls down about $175 an hour.
I hope that helps.