Think about how far you have to place the Sonus Fabers from the rear wall. An absolute minimum of 3 feet, but preferable 5 or 6 feet. Then, how far are you going to sit from the loudspeakers? As a factor of how far apart you place the loudspeakers the listener distance should be 100 to 150%. With these factors in mind, I'm thinking you're going to sit too close to the loudspeakers for them to perform properly.
A phase coherent or driver coincident loudspeaker, like your current KEFs, would be a better idea. Or a loudspeaker designed to work directly placed near the rear wall or corner.
These are not hard and fast rules, but suggestions. I imagine someone somewhere has a really big set of Wilsons placed in a smaller room and thinks it sounds fantastic.