Chimbu
I am impressed. Snap but in different areas. But I still would not be stood over. I would politely suggest you go find someone else to do it for you. And by the way it was in a testing environment that you framed the comment. Not a training environment.
Centaurus.
As you suggest, candidate gives you a boot full of wrong rudder. The throttle is still on the forward stop. Reintroducing full rich will give you intantaneous power. The engine will bark, but you will be on your way. And by the way if you do your failures without guarding the rudders, your a mug. My size 10's will overpower most candidates input fairly quickly when time is of the essence. Also as I said. Do it at the end of the endorsement, not the beginning. The guy should be on the ball. If you have incorrectlty asssesssed the level of his learning, perhaps you should reassess your own reading of standards.
Aerocat
A tad ultra conservative I think. May be appropriate if you are working out of real airports with bags of bitumen, however I woud never employ you for work in the bush.
Maui