Thanks for the input.
The room is 30 x 18 with 15ft tall ceilings. I believe the sensitivity of the speakers is 88db, but I'm not 100% certain of that. The 956 is 240wats at 4ohm, not 500, so that is a sizeable difference. I've thought about adding a preamp in front but the Exogal folks have done their homework and adding one seems to add a layer, so I'm not super excited about that. I haven't ruled it out entirely, though!