How much you charge really depends on what kind of theatre they are. If this was Seattle Rep then you could charge a lot more than you could for a non-union theatre. Few of the local theatres have much money, so most of the actors and tech people are working long hours for little or nothing. You might ask for $50 a rehearsal and see how many they want you to come to. You could get 10 times as much for film, but this isn't film. Since this kind of gig is similar to fight directing, you might contact safd (society of american fight directors) and ask what is scale. hope that helps.
