Well looks like we are delayed. I will investigate the the achievement time stamp. Trust me I know how easy it is to forget the UTC time stamp in the screenshot. I would be ecstatic if everything could be verified from just the achievement.
Edit:: I added instructions to the first post explaining how to take a screenshot with the UTC Clock window present. This can be found under the section that details how to verify boss kills.
If this were even remotely like a "race" you'd see more participation and your rules would be well within reason. As this is nothing like a "race", you'll see very little participation, and the rankings will not be a true reflection of the top guilds in SWTOR.