You should be comfortable in your stretch set position. Looks like tension to me...from there after the body has a good relaxed pose you want to check where the weight in your body is. By watching how you get to your lift you can tell the weight has to shift back...watch your hips rock back to get to a balance before you actually get to the top of your lift. This is wasted energy and time, you should be able to lift without affecting the weight in your body. An easy way to check is to access where your head is...if you can work on being backside loaded...with the head over the back hip then you should have centered up your weight and now you can use it effectively instead of it using you.
One step at a time...this weight change will allow your body to be in a better position to deliver a quality pitch. There is more...but you can't fix anything after the hand separation until you clear up the foundation of starting the pitch.