Different front and rear track

[Talonmotorsport]

My chassis is 1218mm wide at Br11+12 and standard width at the front. I'm using standard width RS3+6 and standard wishbones. Now I know I'm going to need either bolt-on spacers or some deep dished alloys on the rear so the tyres clear the chassis, but how much difference will it make if the front and rear track are different by 100mm? Should I be making 2 or 4 bolt on spacers?