Here's the finished mod. The visual result speaks for itself and the Lace Hot Gold pickups are awesum. That extra humbucker switch is located spot-on too. Thanks for your great service Johnny. You're a Star.
I eventually opted for a Serial/Single Coil/Parallel circuit for the humbucker as it offers more tonal variation than the S/H/S option that we originally discussed. It uses the same DPDT ON/ON/ON switch.
Cheers Austin, definitely a real player's Stratocaster, rock out man :)