One slight drawback on the spin-draw is the hammer cannot be safely cocked until the barrel is all the way up. So, with spin-draw, the gun comes up to firing position, then gets cocked.
What I was taught is to cock the hammer as the hand is pulling the gun from the holster.
Wait, the demo has the hand already on the gun.
In the quick-draw shootout, hands have to start at the side.
Oh, well, it's all for flash and show.
It seems to me that the over-hand draw (wrist making the flip horizontally) allows the hammer to be cocked while the gun is being brought into position, allowing for a trigger pull sooner.
On the other hand, the wrist twist does cause the muzzle to cover the body, and it is possible for a guy to put himself out of commission. This is probably why the butt-fwd over-hand draw is banned in some quick-draw competitions.
A really good gunner is going to start the hammer cock just after the barrel clears his belly. It will be fully cocked when in position. A really bad gunner is going to leak his lunch on the range.
Bruce, this video was posted about two years ago. You probably perused it at the time, learned the technique in your sleep, and when you awoke you just "knew how to do it" (like Snipes in Demolition Man).
Really cool that you can!