I actually played around with making them smooth, took a junk panel and did a couple things, its way easier to use some sort of filler material then to actually sand them down. When I was playing around with it I did both ways and it took about an hour to sand down just a little bit of the panel with a DA and get it looking good. Took about 40 minutes to do it with body filler but that was letting the filler dry and sanding and then do it again. I liked how it came out with the filler alot better