I tend to shoot for something above minimum - in my mind 10-15% as the base start salary, unless there other circumstances.
I find many theatres expect SMs to work for Minimum since it is already higher (On most contracts) then the actors.
I will sometimes forgoe my % over minimum if I can get so something else in return (able to hire my own assistant, billing, extra time off, etc, etc). It's all a crap shoot sometimes, but if they are interested they will entertain any offer.