Hmmm. Let's see... You gotta 19x13' open room, average efficiency speakers, and ya want headroom? Man, as much as I'd love for you to hear the Songtower/i34 combo, I'm not 100% confident that 35 wpc will be enough current for ya. Sure, it'll be fine for jazz, vocal, folk, and acoustic oriented music - but in a space like that, I wouldn't count on it beastin' rock and big scale orchestral pieces.
Given your room and stated needs, I'd take closer look at the Rega Brio R. It seems to be hitting on all the key things you want. Whatever you end up with, I concur with Rollo's statement - the SongTower's tend to sound best with a warmer sounding amp.