I'd go back to scent pads for a little longer. What you generally see is your dog in the beginning searching around like your dog on that track. What I look for is my dog clearly working the edges of the scent pad and never leaving it. At first its good if they leave it a little and then come back, that's them making the right association with the disturbed ground.
I think its generally a couple weeks like Jim mentioned, and 3-4 at a time every day before I see that. Your dog looks like he's got the drive for it, he'll probably be a good tracker.
Awesome, thanks for the help. Videos to follow.