how wide and what offset are your wheels??
a +40 offset wheel with a 5mm spacer will basically make it +35, make sense?
flush for the front is about +33 with a 7" wide wheel (this is what i had).
flush for the rear i would guess to be about +25 on a 7" wide wheel (i was going to go with this)
spacers can be found on ebay. with slip on spacers dont go thicker than 5mm, anything thicker should be done with bolt on spacers, or extended lugs.