We currently have 17x8 with a 45 offset on the rear, with 255/40/17 tires. I wouldn't want them to be any closer on the inside. Using this calculator here , to run a 17x10 wheel and have the same clearance, you would need an offset of 20. Of course this is not accounting for all factors and I don't know how your spindles change things.

We are planning on running different race wheels likely, 15's up front and 17's in the rear for the most tire choices. For dailies, these are Enkei Pfo1's, 17's all around.

Here's a photo of ours, alignment not yet set: