I am not so concerned about the size of the boat that can be accommodated, our course is set up such that the 1/72nd Bismark that shows up can run it. And we usually have two boats on the course at the same time.
What I am looking for is some judging standard that can be used on different courses, at different locations, being judge by different people. In this way we can have a regional competition, at several locations, tally the results and determine who, from the various locations, won.