Been away from the thread for a while . . . .
What if we use two fields to muster instead of just the one performance field? Launch fifty on each field, and then have the fliers on the second field walk backwards to join the first fifty on the performance field. I know it goes against competition rules to walk onto the field with your kite in the air, but this isn't a competition. Then there's less total unwinding and winding time required as twice as many fliers can be launching in twice the space, and many can stage their kites with lines unwound on the second field. As long as the ropes between the fields can be (temporarily) lowered, and as long as the fliers can walk backwards with their kite in the air, this would double the space available for launching. In 2011, rev fliers pretty much took over two of the fields anyway, IIRC. As long as there is no scheduled competition or other event on the second field, I'd think this should be possible.