Your Krells are probably one of the few amps up to the task you’re asking of them.
If you play with the phase of the speakers as you have them set up you might be able to cancel inter-aural cross talk as done with Polk’s “SDA” arrangement.
Another alternative would be (and your rather large room could be quite helpful in this regard) to pull the main speakers well into the room with at least 8’ and preferably 10’ from the listening position and place the second pair directly behind the main speakers facing the opposite way as far as you can from the front wall (as seen from the listening position) maintaining correct phase. The somewhat unique time coherence of your Thiel’s are plus in this setup. This will energize the room much the same way that occurs at live events. Approximating an omni dispersion. Room reflections become much more critical in such an arrangement. Again your large room is quite advantageous for this.
Should you decide to try these options, I would be most interested in reading of your impressions, as I’m toying with the idea of doing similar things with my smaller Thiel’s in a smaller room.