Thanks Drewdog for the link to the 70GTO.
 
The instructor is correct by mentioning by adding the flex agent the paint will soften so it becomes flexible enough, however will only REDUCE the possibility of cracking.
 
He forgot to mention is that by adding the flex agent to the colour the colour will also become soft. Because the paint is soft it is impossible to buff a high gloss back into the paint. The only answer is off the gun gloss (ie no cutting or buffing).
 
Best to dummy fit the nose cone on the car and pull into shape BEFORE ANY paint is applied AND space the nose cone a few millimeters away from the front guards so there is a small gap for masking etc. After the paint is cured carefully remove the spacers and final fit. This will reduce the possibility of the paint cracking around the sharp radius where the corner of the bonnet fits.