Powder coated paint isn't any different to paint over than standard paint. Prep it well by sanding it first to scuff it up and loose the sheen so new paint will stick well, then wash it well and wipe it down with mineral spirits first. Tractor supply paint will work fine, but it's not great. Actually have much better luck with standard rust-oleum but don't think it comes in Kubota orange. Brush it on or spray dosen't matter as long as it's done in the shade and it's over 50 degrees outside, just MAKE SURE YOU USE HARDENER. You can find that at tractor supply in small bottles in the paint section, follow the directions. You can add it to any kind of automotive style oil-based paint including the rust-oleum. Your coat will then be 10x more durable than the standard paint alone. Paint is pretty much useless without it unless it never gets touched or handled. Hope this helps.