Wheels and Tires on the 65 Dart

I am considering purchasing a set of 15 inch Cragar SS rims for my 1964 Dart GT with stock everything. I want to convert to disc brakes in the front in the future. I do not desire rear disc brakes. With that said, I want a wider tire in the back and a slimmer tire in the front due to manual steering. What tire sizes and rim backspacing should I buy?
15x7" and a 4" backspace fit on the rear with a 225 60 or 70 series tire. I kept the 14x6 on the front except for the latest which is a 15x4''.

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