RE: flying behind the flightline
I think it's a bad solution, to set up adjacent flightlines. I want to fly at a flightline where I know no one's flying behind me, or off to my side, within a range of about 400'.
I have seen a novice with a helicopter, flying at the North end of a North-South runway, let his model get away from him. In about 2 seconds it was behind us flyers, behind the spectator line, and on the South side of our shelter, doing the chickenwalk. It covered almost 300' in a flash. Luckily no one was hurt.
In my opinion, 400' is not too much distance to ask for, when placing flightlines near other flightlines. Even better, let everyone take off from the runway, and move the models out over the flyover area for all maneuvers.
Best wishes,
Dave Olson