Well you've got an OT that's set up for 6L6's so maybe a Twin, Bassman, etc? There's lots of amps based on 6L6 output, got an idea what you want it to sound like? You've got 4x power tubes so hopefully there are some other OT taps that will let you use 2x tubes and the speaker impedance you are looking for.
I've never looked at a PA amp before. Why on earth would it have reverb?