Interesting but you need more explosive activities. None of those lifts seem to use fast twitch muscle fibers. Try to include some olympic lifts, jump squats etc. Always think about explosiveness.
What is this decline you speak of? The last time I checked he had just upset the hottest player on tour who was having the greatest winning streak ever and against all odds played the best match against Rafa at Roland Garros that he has ever played. And he's the oddsmakers favorite to win...
I used to have this problem but changed my grip so that my hand was not so far down on the grip. Not only did this solve the annoyance of the bulge of the buttcap but it gave me greater consistency and protects my elbow and wrist from injury.
He needs to take a year off, find his focus and purpose in life and then come back if he decides tennis is what he wants to do. Oh and he needs to work on getting rid of his negativity.
Yeah I just had another look at the close ups and it may be smaller than 1.28 (16L). Maybe more like 1.23 (17) but it's really hard to see from the pictures.