Hey man, looks like you are working hard, keep it up! A couple things. As far as a trigger for your wrist hinge. Check out this thread about your trigger finger:
http://thesandtrap.com/t/57531/the-importance-of-pp3-lower-hand-index-finger-against-the-club
When I separated my right hand index finger slightly it helped me feel my wrist hinge more. The hinging action for me happens pretty naturally just from moving my arms into position in the backswing. The newest video of the drill it looks like you have maybe have a bit too much hinging since your arms havent gone very high yet. You might try having more forward press at address.
One other thing I noticed, your hips seem kind of out of sync with your arms. Check out this video by Ben Hogan that I really like. He really shows how your arms should be connected to the rest of your body during the downswing.
http://www.youtube.com/watch?v=EtleMCfvy3I
Hope this helps, good luck!