I've got nothing against a 255, I simply mentioned a 245 as it is just a little easier to fit under the car without wrecking things. Hard to get away with more positive offset than +35 on a 9" wheel though guy, even that size will contact the rear trailing arm in some cases.
You're right that the front is where the magic happens, but I was guessing that OP was just starting out so in his case I'd avoid a staggered setup simply for economic reasons.
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