65 Barracuda, best width and backspacing?

Hi guys, hope all is well. It's time to ditch the rollers for some more permanent wheels (crager eliminators), and I'm wondering what the best offset is for stock wheel wells on my 65'. Was wanting to maybe run a 7" wheel in the rear, and a 6" in the front, but I'm not sure which offset I should go with. Thanks for the help guys!