Following the SKOSH chart - your experiences?

I've got a friend with a 69 Sport Fury convertible C body. We did a suspension and brake upgrade. Firm feel upper arms, strut rods,lower control arm plates, poly lower control arm bushings and strut rod bushings, solid tie rod sleeves and disc brakes on his drum spindles. Anyway skosh chart doesn't apply to C bodies. Any suggestions? Street driver with radials.
Why wouldn't it apply to C Bodies?