Everything you need to know about heroes, and more

I recommend testing the crit distribution using unbuffed normal attack on ordinary mobs (in a map containing just one type of mob, for preference). Then the question of Chance Attack, or how many Combo orbs were charged, doesn't come into play.

I also recommend it be done by someone with a packet sniffer, or "private server", that would make it possible to automatically and accurately keep track of all damage numbers (crit and not). Working with a video and manually copying the on-screen numbers is way too laborious and error-prone for my tastes. (Alas, I don't have either a packet sniffer or a pserver, so can't do it myself).