Stage volume problem + solution? 210-65

Hi folks,
I'm playing in a group that has a violin player, and I'm wrestling with keeping my sound (loud, semi-clean) while allowing her to hear herself.
I was thinking of disconnecting one of the 10" speakers and then switching the output X-frmer to 8 ohms. I just tried it and it sounded pretty good, but am I am I asking for trouble on the tube,Xfrmer,and speaker fronts?
I've tried the low power mode, and it's ok, but vaguely unsatisfying.
Amp info: 210 sixty-five, 12ax7 PI, stock speakers.
-Matt Sutton

Amp itself will be ok but the speakers in the 65's are pretty flimsy. Unless you are playing pretty damned quiet, I'd leave both speakers connected and lay some foam rubber in front of one of the speakers. Does the same thing but still allows both to work. Used to do just this at one place that we played SO quiet that you could hear the waitress make change in the back row!