Krobar - I assume you are talking about pedal/torque turns when you say 40kts - entering at that speed puts a lot of strain on the tailboom - would you try to fly sideways at 40kts normally? The proper technique is to anticipate the top of the climb and start the yaw just before the horizon (viewed to the side) stops moving relative to the window - that way you initiate the yaw at almost zero speed and get at least halfway round before the descent starts.
As for overstressing the aircraft, the most likely time is during the initial pull-up, whether for a wingover or a torque/pedal turn - that is where the inexperienced tend to be ham-fisted and pull too hard.