It's wired in two sets of a creamback and gold in series, and then the two sets are wired in parallel.
Series + parallel with 4 speakers @ 16 ohms results in a 16 ohm nominal impedance for the cab.
If Celestion sold a g10 neo Creamback I would have bought it. Only available from Celestion in the g12 format.
Edited: to add the following:
The Greenback + Gold "Ace Mix" configuration is
.
The weight is manageable and it's super easy to move with the newly installed Mesa Trak-Loc 3" casters. This is now my go-to gigging cabinet since it sounds excellent with whatever amp feeds it.