Excellent idea, not the best event for it though. Even though gardens are great, I would extend the options far, since most people can't be flexible enough.
The event would probably go like this:
x3-5 Main Judges; their votes count the most, however, if ties come in, this is where Semi- Judges come in. All of these are staff.
x5 Semi-Judges; Their votes count less than the Main Judges, however, their vote can still be significant. Required an OG rank, MVP, or staff to apply.
Since there are few judges, I would add teams to the building competition. 2-player groups get 20min, 3-player 10min, etc.
Excellent idea, looking forward to it soon!;)