Are the fenders the same height from the ground as before? If so I'm pretty sure a stock-diameter tire would smoosh the fender when the suspension compresses, so assuming you want to make use of the wide body and have the tires sticking out (past the normal fenders) you will need a smaller diameter tire. Not sure how much smaller you'd need to go; maybe jack up the knuckle until the spring is fully compressed and measure from the centre of the hub to the fender.
If we consider that a 10" wide, +23 offset wheel fits fairly flush with the stock fenders (front) and you are 2" wider, with a 10.5" wheel I guess you could have an offset of up to -21mm or so (about 1.75" out from the +23 offset wheels)? If that makes sense then the rears could have an offset of about -13mm before they become flush with the new fenders.
Nice wheels by the way
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