First question is easy. Yes. Many play several tables at one time, although it's hard to do on any site other than Party.

Second question isn't so easy. Multi-table SNGs can be profitable, to some. I'm not sure how +EV they are, as you said, the variance is a lot higher. One of the reasons a lot of people play SNGs is to cut down the variance that often comes along with cash games. I play them because they just fit me better. MTT--SNGs are often higher than I'd like.

Since I'm playing 2 table, I can give a little help. You need to pick up chips as you can, but don't be too loose. The real game doesn't begin until the tables merge. If you are short-stacked, it's much harder because you're now on a full table with blinds that are already high. That's why they can be a real challenge, as it can easily become a push-fest or you get blinded out. Just what to push and when to push is something most have a hard time with. I think that luck to skill ratio is a lot higher on multi-table SNGs, but I could be wrong.

Let us know how you do.

CJ