Wheel and Tire HELP?

[SilverBullet68]

Hi Guys,
I'm new to the sight and very appreciative of any feedback. I'm to that stage of my project of new wheels and tires. I have a 1968 Camaro and have been researching online. I have installed Master Power, power discs brakes up front DSE upper and lower A arms, and Hotchkis TVS kit. Out back: I went with a MP drum upgrade and a kit that relocates the shocks inboard of the leaf springs from Performance Online. I want the FOOSE Nitrous II wheels with BF Goodrich KDWs. I'm ordering my wheels and tires as a package online and am saving about half a grand plus they come mounted and balanced. I have only one chance to get the size and offset right as you cant return them.
Detroit Speed and Enginnerring "With the stock suspension, the largest front tire is a P245/45R17 on an 8 inch rim. The largest rear tire is a P275/40R17 on a 9.5 inch rim."
My real dilemma is the backspacing front and rear. ***With that shock relocation kit, what is the widest tire i can get back there??? FOOSE only makes those rims in a 17x8 or 17x10. Also if you guys know where I can get a good deal on the rims and tires online?
Thanks!!!