Upcoming Vegas Visit - Size of Bankroll Question

I am planning an upcoming trip to Vegas for a long week-end (4.5 days) of 2 poker sessions per day - some cash, some tournaments (<$100 total buy-in plus re-buys). I usually play 3-6 limit or $0.5/$1 NL on-line.

Two questions:

1. How do these on-line games "translate" to B&M - i.e. 3-6 Limit = 3-6 B&M Limit?

2. What bankroll advice for B&M $1/2 NL? Obviously I don't lose consistently on-line, but I also don't end +$$ every time. Positive EV over enough hands on-line.

Thanks!

Beachman