Mike and Scott,
Have you looked at my post on page 5 under the title "More Pics"? I have a series of pictures I took of my son. His motion is for the
underhand release, but the starting position is the same.
The dropping of the pouch hand starts the angle of spin in the vertical direction for an underhand release like you mentioned Mike.
When I throw overhand, I start the stone in the more overhand or 45 degree angle by swinging the pouch hand horizintally to release it. Also, after reading my first post I noticed that it sounded like I"stopped" the motion at release and just let the stone "drop" Actually, I am kind of throwing it out to my left to give it monentum and keep the cords tightly outstrecthed. From there the throwing hand takes over.
The only time I feel the need to do more than one rotation is if 1. The sling length is to long to get good momentum in just one rotation. Anything over about 36" 2. If the stone is too heavy to get good momentum in just one rotation. About fist size.
I have tried to see if I could get more power with more rotations, but with the excepts mentioned above, I have more power with just a 360 degree spin.
It really is the last split seconds and the whip motion that lauches the stone.
And as always, I've only done this since August so I make no claims to be an expext. I would guess though, that because of my great place to sling, I probably sling more stones every week than most. I just love the challenge of getting accurate with sure a difficult weapon to master. But, I must say, moderation is prudent. Last week I went out on Saturday and slung for 2 straight hours! My arm was fine but my back went out of commission for 3 days! I walked around bent over like an ape for those days until I could get in to my massage theratist.