On the first one just one. The marring on it wasn't too bad.
I used HC/OP on the first since the marring wasn't too bad. Just one pass took care of it in most spots; required two in a few.
On the second vette I used EC/OP, two passes mostly. Three on the rear deck and rear (the rears on vettes seem especially resistant). It hazed up like a mother, that's why I needed IP before 106FF to get rid of some of that.