I always did my base metal work, put on my filler, knocked it down with 40 grit then 80, then a 120, and then I'd apply a finishing filler and sand that with 220 then 320 maybe even 400 then apply my primers. I suppose its not even really necessary to apply finishing filler if your spraying a 2k primer though huh? I cant remember where I learned to do it the way I have been but it stuck. There was a reason behind it I just cant remember. Owell. Ill be ordering 4 rolls of this paper soon since I'm almost out of my cheapo rolls I got at the local jobber.