I’ve been painting for a long time always looking for the perfect finish color sander. What I have been using for several years now with perfect results is a $40 10” random orbital buffer. I use a lo tack glue on the bare foam face of the buffer and stick a full sheet 9x11 sandpaper on the buffer. Start out with a light touch and then start moving the buffer. The large sanding area spans a large area giving the perfectly smooth surface. Works great for me. Get mirror like finishes. I use a Sata guns and mostly SATA gravity feed touch up gun to get my best finishes.