Auto body repair & detailing: automotive paint, acrylic enamel paint, paint hardener

Question
(1)  WHAT IS THE BEST THINNER TO BE ADDED TO ACRYLIC ENAMEL PAINT WHEN YOU ARE PAINTING A CAR BY BRUSH ? ( 2)  DO YOU ADD PAINT THINNER  TO ACRYLIC  ENAMEL PAINT ALONG WITH PAINT HARDENER  DURING BRUSH A TRUCK BODY ?

Answer
Norris, It would be best to add acrylic enamel reducer. Acrylic Hardener would be beneficial.  Also if you check with your local paint store they can put acrylic enamel in spray cans, which would make your project look much better than using a brush. Norris you should contact the paint store where you bought the paint to get the proper mix ratio.                          
                                        Thanks, Laren