The Paper Tigers here for many years used the cassette type rudder stocks, But with a safety "kick up" system.
The stocks were similar to the Stealth BUT the aft end was not joined but open instead. there were two bands of shock cord fitted around the stock, one at the top of the stocks and one one at the bottom. This would allow the rudders to be pulled up and pushed down as per normal but if the rudders hit anything the shock cord would allow the rudders to pivot backwards and upwards in an arc without breaking. it worked exceedingly well.