Another "Will these fit?": 18" Mustang wheels

OK so I figured I'd do an update. I got the wheels about 6 weeks ago, test fit the rears and with some very light grinding on the centering lip on the wheels they fit perfectly over the rear axle "hubs". A few days ago I took one of the front wheels and test fit it, with similar light grinding it slid over the hub but hit the outer edge of the hub 'snout'(?) with about 3/8" gap between the mounting face of the wheel and the brake hub. I'm thinking about just adding some 1/2" wheel spacers and longer wheel studs, would that screw up the offset of the front wheels? I'll also use the opportunity to upgrade to 11.75" rotors I've been wanting to do that for a while.