I know that in my head, dgman, but sometimes I don't seem to know it in my hands. I'm at the point where I can do most things pretty well *some* of the time but have trouble with doing them right consistently.
I know I just need more -and more- practice but I want to make one of these (right now, lol). That's why I wondered if there was an easy way to assure the roundness of my circle. I'll cut it freehand and I'll try to make a good job of it but having a sanding jig ready is still probably a good idea. If nothing else, it'll help me relax when I'm making the cut.