Jeff,
Nice assortment of equipment.
Wonder if the low Qts of the driver has anything to do with which amp sounds best. Has anyone else here tried SI/Clari-T/digital amps with horns?
An internet friend assembled the BK-16 and said that the panels were well cut and had no problems. As always finishing is the biggest challenge. But if your quality standards are low, or you're happy with paint/exposed plywood edges, or you can find a trim carpenter to finish them for you the BK-16 makes for a nice little horn. I'd keep the super tweeter off, unless you have very good high frequency hearing or are forced to listen way off-center most of the time.
Another internet friend uses the Clari-T with Bob Brines FTA-2000 (transmission line cabinets with Fostex F200A drivers that are only rated 89 dB/w/m, 8 ohms, 30 - 20,000 Hz in room) and its a match made in heaven with sufficient volume for all but the loudest classical peaks.