How do you tell if the paint is hard or soft? I had a Honda Civic, Pearl Midnight Blue that all you had to do was look at it and it would scratch. My Toyota Prius, Red is not as bad. My Vivid Black Harley holds up well and buffs out great, I guess this is on the hard side. I just can't tell on the Prius some swirls disappear easily, others I have to work at. Is there a chart or does it all come from experience with many different vehicles and a myriad of products used to detail?