they are coming out with scratches and swirl marks because your are using a final sandpaper with a 1500 grit. much to low. you need to go buy 2000-3000. 2 and 3000 grit paper is basically like rubbing paper on your lenses but will smooth them up and get rid of swirl marks.
you are using to low of a grit to be finishing with. id sand it down, spray it, wet sand in 3 steps 1500, 2000, then 3000. clear it, polish and wax it. should look like sex after that.