Re: P-Rails noise...
Try tilting the guitar around and facing different directions. Also try touching the strings and pickup posts etc, and tell us how the noise is affected. If you have a multimeter, check your various earths with that, too.
I haven't heard of anyone having noise issues with the humbucking mode, and it's pretty unlikely that you got two defective ones. If you really have trouble narrowing down the noise, try taking pots and such out the circuit in a systematic way to see if noise improves. (Or wire straight to output first, then add pots and switches back in systematically).