Matt,
I think your modification of the trapezoid course is an improvement compared to the youth championships. I observed a few problems with the the youth champs course. For one, I don't think it is good to have a giant committee boat at the port end of the starting line. This can get messy. Also, it was difficult to run a new start while the other fleet was still on the 1-4 course. The gate was right in front of the start line (above the RC boat and not as shown in the SI's) so you can have the situation where boats are coming into the gate while the new fleet is starting. And this did happen. Also, the boats finishing upwind can get pushed into the starting area. The best modification I saw was at the Youth Worlds in Kingston. They had one start finish line (RC boat on stbd end) and finished boats sailing the outer windward leeward course (2-3)at mark 5. That way the S/F area was clear for starters or finishing boats on the 1-4 windward leeward course. With the waves starting first, I would think you would have the problem of the 17's catching them on the first weather leg.
Greg