Yeah, this is always an issue when playing small clubs. I'm guessing this was a small club?

A 50W tube amp can be REALLY loud, and usually 30W of pure tube will be more than enough for almost any gig.

Like you, I hate having to play at 1 or 1,5 when I really want to go to 11. :) One thing you can do in these situations is turn the amp backwards, facing away from the audience. Sometimes the drummer will want the guitar amp facing him if he has trouble hearing what's going on over his drums. This way you can turn it up a bit, and the mic'd up amp will come out evenly through the PA system for the audience.

If you don't have monitors facing you on stage, this can of course be a problem since you won't hear yourself as well.