Wolcott 220 compatible with ribbon speakers?

Are you referring to the large four piece Genesis speaker? If so, does this require bi-amp?

I am using wolcott 220 on Apogee Divas with excellent results. I have used them full range and also on the bass ribbon using the active crossover. Very impressive overall

I have been told by another dealer (not a Wolcott dealer) that the best he's ever heard Maggies sound was when driven by a pair of Wolcotts.

I've used 'em on Cliffhanger Bulldogs (ribbon tweet) with excellent results.

The Wolcotts will deliver their rated power down into a 2 ohm load (Henry tells me down into a 1.7 ohm load). Not bad for a tube amp. With a speaker like the Genesis that has a particularly extended top end, I'd strongly recommend you get Wolcotts with the wide-bandwidth output transformer (now standard). The wide-bandwidth output transformer was introduced specifically for electrostats, but any speaker with an extended top end benefits from it. The adjustable output impedance control is also useful for dialing in the voicing of the amp/speaker system.

I'd say as long as the impedance of the Genesis speaker doesn't go below 2 ohms, the Wolcotts will work quite well. Much below 2 ohms, and you might get some compression and loss of contol.