IMO, you must have at least 1k difference in DC resistance to balance a pair of pickups.I just put in some SD 78's in my Wolfgang, 7.9k neck, 9.0k bridge. Great balance, and slightly hotter than standard PAF specs. For reference my burst replica has a 7.6k neck early PAT #, and an 8.7k 61 PAF bridge pickup in it. Easy to set the height/balance and if it's the tone you like, then the 1k offset is right on.
But then you get into all the other variables...unpotted, wax potted, secret sauce potted (Jim Wagner phrase, always loved it!), etc, etc. I have fair amount of pickups in a box because of this. LOL