The popular choice for that set-up is 245/275/35. I went with 255/285/35x19 on my Winnings. The offsets were +19F and +29R. At this time, the car is dropped with 350Z Tein H-Techs and the rear fenders have been rolled.
You can go with a much more agressive offset at the rear if you opt for the 275/35's.
If you haven't already done so, you might want to give Chris at F1 a shout. He will be quite helpful and informative to help you with your wheel/tire combo selection. Good luck and enjoy!