Re: Custom, Custom5 or Custom Custom?
It depends on which coil you use in the humbucker. The screw coils in the Custom series will be oriented South and the slug coil will be oriented North. I *think* a standard Quarter Pound is oriented South and an RWRP Quarter Pound is oriented North.
For hum-cancelling and in-phase operation:
If you want to combine a Quarter Pound with the slug coil then you need a standard version in the middle and RWRP in the neck. If you want to combine a Quarter Pound with a screw coil then you need an RWRP version in the middle and a standard version in the neck.
https://forum.seymourduncan.com/sho...-PU-POLARITY&p=3358169&viewfull=1#post3358169
...and of course a few posts down someone is claiming the polarity on the Quarter Pound is reversed from the post I just linked. Sigh!
If you (or I!) managed to get it wrong and have a phase problem (but hum is still cancelled), you can flip the magnet in the humbucker and reverse the wires you would otherwise use. It may be simpler to swap the neck and middle pickups, provided you left enough lead length.
Case in point:
I once purchased an RWRP SD middle and a standard SD single coil neck pickup and wanted to split to the slug coil of a SD humbucker. The singles were different models so I couldn't just swap their positions. I ended up flipping the magnet and connecting the black wire to ground and the green wire became the output. It should also be noted that the red and white wires were pulled to hot rather than the traditional ground for split operation. If my wiring required me to short the screw coil to ground then I would have had to tie the black and green wires together and use the white and red wires for hot and ground, respectively.
All that said, I still have a feeling that a split Custom might not be hot enough to match the Quarter Pound. I could easily be wrong and hope I am so that you aren't faced with additional complications/unwanted behavior.
Regarding the polarity of the Quarter Pound, if I got it wrong, edits will be made...but only if someone confirms it!