wheel/tire front fender clearance for '68 Camaro

[Rhino]

What is generally considered the proper fender clearance for a front wheel/tire combination? At ride height it seems that I'll have about 3/4" of clearance from the top of the tire to the wheel arch. I'm building my own sub frame and want to stuff the tires as far out as I possibly can without interference. I'll be modifying the inner fenders to get rid of the most common interference points. I have my wheel/tire selection finalized and am finally getting the rest of my calculations sorted out.
I would like to finalize my plans before breaking out the welder, so unfortunately I don't have anything to mock up at this point.

As my plan sits right now, I have 5/8" clearance from the innermost portion of the outer fender lip to my outermost wheel contact point. Is this sufficient clearance? Is it too much? I would like to run them further out, but what has me worried is the possibility of contact under hard braking, in a turn. A scenario that could possibly have the steering at full lock with about 2" of dive/roll.

[Rhino]

In case it's of any significance, I'll be working with -1* to -1.5* of static camber and roughly -3/4* of camber gain per inch.