Just adding my two cents to this thread...
I found that modern tire design and brands, such Nitto do not make many, if any performance tires below 17 inch diameter. On my 70 Mach 1 M-code, I went with 17 US Mags Bandit rims and Nitto NT555 G2s. I have factory height big block constant 640 lbs rated coil springs up front with Global West suspension and a 1" Shelby drop (upper Arm Control). Global West Plus 3 upper arms have 3 degrees of positive caster built into them. This will eliminate the need to pull the lower arm so far forward in order to get the optimal alignment.
In the rear I have stock height 138 lbs rated/Competition Handling Eaton rear springs and an aftermarket 1" rear sway bar. The US Mags Bandit front 17x 8 with a 1 Offset and 4.54 backspace with Nitto NT555 G2 245 x 45 tires. The rear US Mags Bandit front 17x 9 with a 8 Offset and 5.31 backspace with a big Nitto NT555 G2 275 x 50 tires.
I prefer the look of a larger width and height rear tire. I did have to roll my rear fender lips. I also lightly rolled the front fender lips too, but I don't think I needed to.