17" Wheels with KH Disc Brakes

I'm thinking about calling in and ordering the wheels sometime this week. They'll sit in my garage for awhile. I'm thinking about getting 17x7's for the front and trying a 215/45/17 and 17x8's for the rear. I'm just uncertain for the rear tire size for a stock 8 3/4. I was thinking something like a 255/40/17. Any opinions for the rears?

I've got a spare 215/50/17 tire in my garage from my sister's Mazda 3, but they seem pretty tall for the front.