These are the sizes I'm using.
F: 17x8 +40 215/40 tires
R: 17x9 +35 245/40 tires
To sit perfectly flush, the fronts could come out another 5mm and the rears could come out another 2mm.
So, ideally, I wanted this:
F: 17x8 +35
R: 17x9 +33
That being said, it's very very hard to find a rim style you like that is offered in both sizes you're looking for. Sometimes you have to sacrifice a couple millimeters here and there to get what you want.
It also should be said that if you want "flush" wheels, the rear fenders will absolutely have to be rolled. I had to roll mine to fit my wheels.
Best of luck!
Frank