I will try it myself with a fast trainer I bought yesterday and he is currently 79%. I wanted to wait for some offers but screw it it's probably gonna be 5 0T offers before I get to sell him. I save my greens like a fanatic but YOLO lol.
The surprisingly funny thing for me is GK has been one of the least effecting drills in my experience even for GK themselves. I call BS on that and I agree with Nikos explanation.