Joe,
Congrats on the purchase! I own 100s and they should be a great choice for you, given your taste in music. I, too, enjoy guitar music of every variety, including the slack key stuff from your 'hood.
50 to 75 wpc should work well, but I wouldn't dip below that level. Higher power might not be a requirement in a room of your size (unless you like your Allison Krauss at ear-bleed levels), but OTOH, it wouldn't hurt.
I've briefly used a Pathos classic one integrated and a Bel Canto s300 in a room half again the size of yours. Both worked very nicely. In my larger room, I successfully use the Prima Luna 7 tube monos with kt 66 output tubes (good for app 60 wpc). This room is twice the size of yours, but I filter the 100s below 75hz for use with a sub, so we're a bit apples and oranges here. My guess is that the higher output PL integrated might do the trick for your full range application, too - but I'm speculating a bit. The rest of my experience has been with high output power amps so it's not really germain here.
Good Luck.
Marty