I'm afraid you're out of luck.

AFAIK the PPC212 is a pair of 8 Ohm speakers wired in series. If you wire the two speakers in parallel you'll end up with 4 Ohms. There is no way you can wire this as an 8 Ohm cab.

Again, AFAIK

(and if anyone knows differently, please correct me) the PPC412 consists of four 16 Ohm speakers, wired in what's known as "series/parallel". In other words, two of the speakers (let's call them Pair A) are wired in parallel, making an 8 Ohm pair. The other two (Pair B) are also wired together in parallel, making another 8 Ohm pair. Finally, these two pairs are wired in series, resulting in a total load of 16 Ohms.

With a cab that contains four 16 Ohm speakers, again it is impossible to make it into an 8 Ohm cab. You can have:

64 Ohms (all the speakers in series - I wouldn't recommend that!)

16 Ohms (as described above)

4 Ohms (all the speakers in parallel)

The only way you're going to get an 8 Ohm load using Orange PPC cabs is by having either two PPC212s or two PPC412s. Expensive!