One thing,I watched your video of you shooting and could'nt help but noticing that,now correct me if I'm wrong you were shooting on the right side of the bow being right handed.Can you explain the reason for this?I assume you are using a thumb ring.I am not familiar seeing or doing this.
I can answer that for you (sorry, don't mean to butt in here but...). When using a thumb draw the arrow goes on the 'outside' of the bow so that you are shooting off of your thumb and not your fingers. When you hook the thumb around the string, you also rotate the hand INTO the string to keep the nock on the string. This also presses the arrow into contact with the bow and allows you to shoot from ANY position. With this grip and draw style you can hold the bow horizontal with the arrow on the bottom and still shoot. Most ancient styles of shooting used thumb draws and not the 'English' three finger draw.
The thumb draw also eliminates most wrist slap if you're doing it correctly because the string is released straight and doesn't come off the fingers and into the wrist. The Japanese, Chinese, Mongolian, Romans, Sassainds, Turks all used thumb draws.
You can use a hard plastic or horn thumb ring or just use the thumb from a leather glove or make a simple leather thumb ring. (Note: Hard plastic or horn thumb rings take some time getting used to shooting with - I've found that they introduce a measure of quantum uncertainty in my shooting so I use a leather one. ) Def: Quantum Uncertanity - I hit the target or the neighbors yard.
The actual mechanics are: With your hand facing downward, hook the thumb around the string just below the arrow nock. Bend your index finger down over your thumbnail to lock the grip and rotate your wrist so your hand pushes into the string. Pull back to your anchor point and then release both index finger and thumb... it acts just like a quick release.
Easier way to learn:
https://www.youtube.com/watch?v=zg0wmBeoRocor
https://www.youtube.com/watch?v=dX8UQEmXB7s (check out the bow he's using - NOT traditonal )