FWIW - and going by memory, as the car's not with me - Jack added what looked like about 1/2" to the width (or length, if you prefer) of the front "leg".
We could actually get 8+ pos caster, but 7 was plenty: straight as a string @ 130 MPH, and nothing disturbed that.
Only downside, if I didn't mention it already here, was when turning the car in the lanes, you don't want your hand between the steering wheel spokes.
It would self-center with a vengeance...

BTW: Learned in my BMW & Vintage TransAm racer days to approximate driver's weight in the seat; 1/2-tank of fuel was really splitting hairs,,,