66 Mustang Question

I have a customer that wants to get wheels for her 66 Mustang. She says that it is all stock suspension and ride height. she wants a 15" wheel and i am compiling a selection of wheels for her to pick from. I have done some research but i want the people that know to double check me. she wants to go with the widest tire possible in the rear and a skinnier tire in the front. this is what i have narrowed it down to

Front: 15x7 wheel 4.25 backspacing and 215/65R15
Rear 15x8 wheel 4.5 backspacing and 235/60R15

there is only and inch difference between the widths on the two tires. should i go with a skinnier tire up front to give it that old school dragster look or am i asking for trouble with wet road conditions.

here is some additional info on the car
1966 Mustang Coupe 289 V8 automatic
she says it has disc brakes in the front but wasnt 100% sure.

thanks for the help!

are these cars hard to find wheels for? the backspacing i have to use is nearly impossible to find. they eaither make the wheel with 4.25 or 4.5 i cant find any made with both...

ok maybe i am starting to figure this out. i would have to buy a set of wheels at 4.5" backspacing and use 1/4" spacers in the front in order to get my 4.25" backspacing correct? or am i totally off the mark here...its a shame that i can build engines, transmissions, rewire cars, rebuild and restore suspensions....but i cant fit some darn wheels haha