Thanks Wayne,I figure I'll play around with PiAlign, BoxPlot, WinISD, and maybe some other programs before settling on final tuning. Since I will be using them for 5.1 HT duty I think 100-150hz should work reasonably well. Obviously the lower I can go the more seamless the transition to the sub will be. I plan on following your lead regarding the X-over, allowing the Alpha6 to roll off at around 4K.
Greg