Just in my opinion, correct me if i'm wrong:
For an amp like that, a 10" or 12" speaker amp would help in bringing out the bass frequencies that are usually lost in the 8" speakers. Weight is a consideration if you're bringing it out often enough - amps tend to be heavy. A 1x10 or 1x12 combo if you want the whole thing, and a head if you can plug to speakers elsewhere.
For tube amp wattage, often they're loud enough for practice and jamming. (Sometimes too loud, especially if you're looking to crank it for tube power amp distortion). Solid-states usually are linear in volume on the other hand.
Gig-wise depends on location. If miking up is ok, I don't think there's a problem whether you use an amp with less or more wattage. There're very few tube amps which accommodate practice and gig volumes with the same quality of tone though. (In any case, the human hearing prefers louder volume given all else equals.)
I think perhaps you should state your budget and your tonal preferences first.