the only thing i would add to this, is after your last coat of primer (i assume its grey) give it a quick "dusting" in mat black or any other apposing colour, then with your block use a 1000 grit and go over any flat surfaces till the dust coat disapears, this ensures you have no high or low spots. also words to live by when prepping " IF YOU CAN FEEL IT WITH YOUR HAND, YOU WILL SEE IT WITH YOUR EYE WHEN ITS PAINTED!" hth ;)