So far, these two gave me the best answers. anyway. regarding the Sennoc vs the LeeD debate. i will side with Sennoc on this one.
Here is why, pure pronation has no impact on the ball. Try it, just keep hitting the ball with pure pronation. Mind you pronation is simply applicable to the forearm so you can't move your elbow or your shoulder because then you are applying internal rotation into the action.
so why is continental or EBH is the optimal grip for serve is because it has the less wind resistance. you are basically hammering the ball but to avoid the frame you pronate at the point of impact because that's what you want to hit it with. but by using continental or EBH, there is less wind resistance and less and it's better biomechanically because you can coil and explode with it. unlike EFH the coiling is almost impossible because the way the racket is held is already internally rotated.
so from what i learned, pronation doesn't put spins on the ball it's actually the internal rotation of the shoulder. Pronation is basically the way of contacting the ball, either you want flat, kick, or slice. and if you actually review every shots the follow through is different but they all have pronation. so the shots are affected by elbow and shoulder movement but not by pronation
in continental grip, you can go from external rotation of the shoulder to internal rotation. while efh the arm is already internally rotated therefore losing that part of the energy.