
 Originally Posted by 
WeirdBits
					
				 
				Sorry Stefano, I didn't realise you were asking a question.
Your compass indicates that the humbucker's screw coil is magnetic south, and the TDPRI link appears to show that the green/red wire pair are connected to that coil.  That means the north slug coil is the black/white pair.  If your bridge single coil is south polarity as you've stated then you'll need to split to the neck's black/white slug coil to get a hum-cancelling coil pair with the bridge.  That means rearranging the mini-switch connections to split to the slug coil. 
It's possible you may still have phase issues, particularly if the two pickups are different brands/manufacturers.  It this is the case it will sound thin and nasally in positions 2 and 3, regardless of the mini-switch setting.  In that situation swapping the black and green connections on the 4-way switch should solve it.  That is, black would go from the mini-switch to the top two connections on the 4-way and the green would go to the lower left connection instead.