Strike, I know that when there is filming of catchers at PG events, they film the throw to 2nd from behind 2nd base. That gives you a good view of the catcher's arm action as well as whether he goes too much to one side or the other as he throws. I did some video for my son and had game footage of him, which I edited to show him blocking balls, throwing to 2nd, throwing to 1st on a bunt, catching a foul pop, etc.
As for the rest of your question, you might want to ask a couple of the coaches on here...I can tell you that I have been told that they are looking for soft hands behind the plate, a guy who receives well, and has good mechanics on his blocking and on his throws. Kentucky's coach told me once that a college catcher might catch 150 pitches in a 9 inning game, and only throw to 2nd twice...they want to know how a guy handles those 150 pitches, not just how fast he throws to 2nd.
