Jbell did you look at the kicker L7's?? Really wish I was better at hornresp
The 12's are too big for your space (frame 12 5/8") so I checked a pair of 10sl7's and they were within a db of the titanic's with same cabinet size and a pair of 4" diameter, 16" long ports. They are safe xmax down to 30hz at 500watts per driver.
I know you like kickers -- the 10sl7's would be fine.