I'm not usually a fan of gizmos such as this. But here I think you yourself need to clarify what would constitute proof, to you?
High runs etc are contigent on many factors, such as mental acuity, vision, aiming, understanding of the game (pattern play, risk management) as well as the stroke. Also we all have cyclic performance swings to varying degrees, caused by numerous physiological and psychological factors. It would be pretty hard to isolate not only the effect of (possible improvement of) the stroke from those other factors, but also any kind of placebo or nocebo effect the device might introduce.
Personally I think a valid test would be a battery of shots with position as well as pocketing requirements. Like shot number one from Bert Kinisters first tape and other such stroke tests. Admittedly it would be difficult to get it to scientific level, if not impossible, but you'd get a good enough idea, I'd think. A number of trials over a period of time would be needed, with no specific practise of the test battery inbetween.
I believe in coaching and self analysis (video assisted) myself, but the above is how I'd test it.
That’s all good by me.
But so far none of that has been proffered.
Lou Figueroa