I had the single 12 version with 7591s and a master. It was called the ThunderStar.
The seller told me it was a Jazz-type amp, but he was wrong. Strictly Rock and Roll. In fact, it sounded like a 20 watt Marshall, if you set the controls right. It was a little too loud for my band and I gave it to a friend who has a studio in a nearby town. The vibrato thingie was broken and the schematics didn't have a value for it, so we put a Fender Vibrato thingie (LED? I can't remember) and it triggered entirely too fast.
The 12" was in a poor man's tone-ring cabinet. The speaker was on a second baffle board a 1/2" behind the grill baffle and all of the back side air would go around the sides and exit with the front speaker waves. It was probably sonically identical to a ported cab, in that it would have been hard to tell in a blind-fold test. Very heavy.
All of those '68-69 amps were built well. I have one of the older Beige T'Bird amps, that sounds like a cool lounge act amp out of the '70's. The 7591s sound kind of plasticky by themselves, but work very well with reverb, etc. I would have loved to own that amp when I was 20 or so!
Enjoy your amp, hope the vibrato works! HH