Re-driving an old GK cab: GK 4412H Extended Range Bass

[DieselDentist]

I'm sure a few of you will be familiar with these. It's a 4 x 12" folded horn, with 2 x 10" forward facing speakers. I can't find any good information on how this is supposed to be wired. The 10's have two filter caps inline. The 12's are 16ohm speakers, and the plate says this thing is 4ohm. The two tens were blown, so I stuffed some eminence deltas in there, each 8ohm and wired the 10's in series, and the rest in parallel. Effectively treating it as 5 - 16ohm = 3.2ohm load. The 12's, even though several are re-coned, I can hear bottoming out the voice coil at live volume levels.

The deltas don't have as low a frequency response as I'd like, but as the two forward facing with caps they should be fine.
The Delta 15 = 64 to 4,000 Hz
The Delta 12 = 65 to 5,000 Hz
The Delta 10= 71 to 3,700 Hz
The Delta 15B speakers I have in a 4x15 Sunn cab sound pretty god, tuned to C standard. But with the Low G on my 5 string, it just comes off farty though.

The question is what speakers to use and how to wire replacement 12's?
Do I run 3 sets of two 8 ohm speakers (16 - 16 - 16) for 5.3ohms
Or do I run it like it's wired now, at 3.2ohm?

8 ohm bass speakers are easier to come by. My amp has 2 and 4 ohm taps. I'm inclined to run it at 5.3, which should work with my 4ohm cab if I wanted to double up. The 3.2 configuration might be too low or two low with another 4 ohm cab? I know there's some wiggle room.

Any advice would be great.
Thanks, -Paul

[DieselDentist]

I'm thinking I'll be going with some Legend BP122 - 12" speakers and set the cab up to bi-amp for my new Verellen Kalaloch head. Put the 12's on one circuit and the 10's on another.

[SquareWaveFuzz]

Have you looked at the low frequency versions of the Delta's, the Delta 12LFA has a frequency range of 44Hz-3kHz?