I'll probaly use 14.5" for my calculations.
I'm currently attending a suspension seminar. Most of the instruction is patterned round full size cars (Late Models, Modifieds, Street Stocks, etc.).
Anyway, the interesting point is the instructor said to use 15" as CGH in his formulas. So I guess it (CGH) isn't too dependent on the size of the car.
And thanks for your reply.