Tire Size for staggered fitment on 350z?

okay so the rims im gettin are 18x8 front 18x9 back. Now my question is what tire size is going to fit this? ive read a lot on forums but just never really had my question answered. Discount tire says 225/45-18 front and 265/40-18 back. just wondering if anyone knows this setup is correct or have this setup.|||I would recommend 245/45/18 front and 275/40/18 Rear. I used this set up for years on my 800 horsepower fully built 350z before I sold it. However, I would highly recommend a 10 inch wheel for the rear, it will help with the stance, trust me :)|||jkl;