If you want to advertise your event in MA (Model Aviation) and have a "sanctioned" event get some one who is an AMA CD (contest director) to be in charge of the event. If you don't care about sanctioning the event then that's not necessary. If it is a contest then you should probably use the AMA scale contest rules. You can down load them from the AMA net site. If you have judges then they need to be "trained" to help avoid lots of arguments. The more preparation you do ahead of time the better the contest will run.