The primary ratings are obvious, the secondary rating that means the most is patience. The rest of the ratings mean anywhere from zippity-do-da, to slightly more then zilch.
I go with 50 RL, 55 LOA 60 HIA 65 AA 70 AAA 80+ ML. these are basically minimums, however if a guy has awesome patience Im willing to go with a slightly lower main rating.
Another important rating (in a way) is loyalty, coach hiring is mundane at the MiL levels, and hiring a guy with awesome loyalty is a real boon as long as his prime rating isnt too bad.