So I have a SG double neck which I got off eBay (it was a kit) and I'm looking to install new EMG h4 pickups in it but it has a 3 way switch for the neck selector (6srting,both,12string).

So how much I install these EMG pickups with a 3 way neck selector switch?

It's like the 1275

Is their a diagram I can follow? Any links?

You've got more than just the neck selector switch, right? You should have individual pickup selector switches as well, right?