If you have $400 and are confident in your ring game, 16 buyins ought to be fine two tabling. The general rule of thumb seems to be 20, but if you have the discipline to move down to $10 NL when you take a hit, 16 should be okay. If I were you, I would want a few more hands in at $10 NL since your experience is tourneys, IMHO.....

The biggest difference for me was the fact that you can't loosen up after a while in ring like you have to in a tourney. You have to be much more patient and really wait for good hands to play. The flip side of that is that you have no pressure to force the issue.

Congrats on the house, man!!!