For any scientific data and experiment to be measured you must reduce the human interaction as much as possible, in my opinion especially with billiards stroke. If you want to measure the data of the comparison for shafts and energy transfer; a machine must be used. I don't care if you think you can stroke the same way and same speed. It is just impossible nobody can do that.
I always find it funny when people compare deflection of shafts by using their own stroke and putting some type of a ruler, I am sorry but that doesn't work. If people can invest in developing an engineering robot that does the stroking, then it is hard to come to a conclusion.
I know Bob Meucci made a bot that shoots, with that machine you can measure deflection and also can measure energy transfer all you want, as long as you don't have a human arm involved in the stroking process, but some people don't believe Bob. So my question is how about you design your own robot? Why is it hard to design a robot that strokes the cueball with a certain set of speed, i.e. you can put a variable of speed then maybe manipulate that value, then we can talk about experiments.