coy wheels on my 67 barracuda

I called coy on wheel fitment for my barracuda and i want to use 18x8s and 17x7s ,they said 4.5 backspacing w a 245/45 on the rear and 4.25 w a 225/45 in the front. need your opinion guys if this will b good!! oh ,yea its about a inch or so below stock height,Thanks,Ted