I just figured I would update this thread with my results. I opted to wire the cabinet with 2 sets of 3 speakers in parallel, with those 2 sets in series with each speaker at 8Ω giving me a total load of 5.34Ω.
I plugged in my Sentura II and with much luck it works fantastic. I prefer the sound of these 12" Eminence speakers over my 215S with JBL E140's in it. The 215S sounded good, don't get me wrong, but I get a bit more clarity out of the 1200S cabinet, plus some added air.
Thanks again for your comments!