I think bump-ups are a good option. A couple weeks ago, I won the B-main and ran the A. There wasn't a lot of turn-around time, and thus I wasn't as ready as I would maybe have liked to have been. On the other hand, I knew I wasn't going to win the A, unless everyone else broke, of course.
The best part is that I was able to run with some faster drivers, learn how to hold my lines better (as I was getting blown by on the straights) and generally have a good time. Hopefully, if I can make some A's on quals, I'll have some of the other drivers' respect and have better races with them because of it.
Just my two cents.