One thing to remember is clan's have tags now, it'll be so easy to identify if a clan participated in a count down. Also make it so you have to post a screen shot of battle results and the teams, but posting screen shots won't have a deadline, so people who have to work, school, etc won't have the stress of trying to get screen shots in (but have an appropriate deadline at the end of the contest).
I don't get why people choose a medal contest, because there needs to be a random pick of all people who earned that medal.
Medal of choice I think would be Raider (pure luck), Kamikaze (easy but it's a random draw anyway), Nicols's Medal (most unicoms will get it)