Id just spray it, but thats me. I have no experience with powder, maybe research what they used from the factory and use as close to that as you can?
1983 ATC 185s 200 jug bored .20 9.5:1 Naumura piston. Fast as ass when its not stretching the drive chain or stripping hubs.
1986 ATC 250ES. *Total garbage trying to sell it*
1983 YTM 200E. Runs good, forks are super bent but aside from that its mint.
1984 YTM 200L. Barn find, everything is mint except the bottom end is bad... *waiting on a new engine*