1961 Tire to fender clearence...?

[The1960APE]

After some helpful posts from you guys we have decided to mini tub the 61 project. I already bought brand new wheel vintiiques 16x8 steelies and brand new tires, looks as if I jumped the gun.
Now I am thinking about jumping up to 18" or 20" wheels, possibly Mobsteel (Detroit steel) the plan for the rear is a 11" or 12" wide wheel and a 8" wide for the front.
My question for you guys is at what point will I run into issues clearing the front inner fenders?

Thanks