A staggered setup is really highly unrecommended, if that's a word. I think 2/32 of tread depth on even the same tires is the max allowable difference. I think with different sizes to start, coupled with different wear rates that you'd be a "when" not "if" for cooking the diff.
Why not just get different offset wheels front/rear but keep the width and tires the same. You can get that sexy staggered look without the performance trade off and potential time bomb?