Surly, I spent a good year playing 8-ball in the APA as a SL 2...and yes there were some painful matches that just didn't seem to end....where I felt guilty subjecting my teammates to such horrible pool. But I was lucky to have a couple experienced players on my team who took an interest in my matches, and I improved quickly.
Now when I kick butt, people come up to me and say, "wow, I remember when you could barely make a ball. You just kicked my a$$." Its very satisfying.
There are some teams that will put you on their roster so they can have a SL2 to stay under the handicap limit. They will tell you its your turn to play, and help you if you call a time out, but the rest of the time they're at the bar, checking their watches, waiting for the "real" pool to start. ...some of them will not want you to improve because they may not be sandbaggers, but they don't want you to go up either, because then they will have too many points. I've been fortunate not to be on those teams, but I've seen it.
So, if you're clear about your goals and the kind of support you're looking for from your teammates, I think that actually getting in and competing is probably one of the best ways to get better if your obses...I mean ambitious to be a very good player.
I hope you go for it...