If on the fence, or not, do what I did…a big bold SS (vintage Crown DC 300 no less) with 5 foot tall 4 way vintage Infinity speakers in the BIG room (20 foot ceiling) for the big bold punchy party rock and roll and get the party started! Then when time to wind down, retreat to the smaller room, fire up the SET tubes into a pair of Klipsch and relax with low volume highly resolving jazz or singer songwriter vocals and chill till morning.
Different rooms, different systems, different music choices…best of both worlds.
Cheers!