Make sure you use a high quality brush too as with the cheaper ones do loose a lot of hair. You may find that the paint you have is too thick, I had to apply 2 coats to my lid and my paint did not cover completely on the first coat, try a little paint mixed with thinners and see if that coats better. As to the TD sand it pack again, get some spray can grey primer then coat with a gloss clear, it will darken and it is acceptable for Centurion. Problem solved and no brush marks.