Yo, Justubes,
I owned K-horns for 20+ years. I absolutley loved everthing about them...BUT, the 4,000 Hz - 8,000 Hz peak drove me crazy. On almost all of my classical recordings, they made the violins sound like wire, and twangy wire at that. Higher-pitched brass instruments would drive you from the room with a whanging headache. Their bass was the deepest, most natural I have EVER heard, and their legendary sensitivity made them driveable to full volume on less than a watt. Hell, I could have driven them to 100db with a battery-powered wristwatch! I kept them for 20 years for their virtues, hoping to be able to eliminate the one damnable flaw by experimenting with different electronics, etc. But no luck. I finally sold them, for TWICE what I paid for them, and the buyer was ecstatic (still is) to get 'em so cheap! Now, THAT's value!!
I never had a room that was large enough to space them 20 feet apart, though. The most I could do was around 15-16. I DID hear K-horns, with a derived center channel (the "Heresy," I believe), in an enormous room...it had to be over 40' wide. If you sat at least 30-40 feet away from them, the peak was ameliorated and they sounded fine. The guy (lives in Hong Kong) used vintage McIntosh tubes...25 watts per side. I suspect you are right, that SET's in a large, LARGE room might do the trick. You'd only need 1/2 to 1 watt to fill the LA coliseum! Even though I had no luck with 'em, it's fun to read about someone else who responded so positively to these "old" classics.
Happy listening!
Gerald Clifton