Situation: Filling the last spot in your group...

[falkun]

Screw the min-maxing, send a tell to both and whoever responds/arrives first gets the spot. If you've already fulfilled "the holy trinity", just fill spots. Assuming everyone's a decent player you will kill faster than you would sitting around with your thumb up your butts pondering this question.

Stop worrying about what is "best" and worry about what is "fun". This isn't your job where you are trying to optimize your work, this is a game where you are trying to enjoy the time the most.