Okay, first of all, you're overthinking it. Any of the planets I discussed will work for you. Mercury is certainly an option for the kind of job you have. Jupiter is also an option. Choose one and do it.

Second, your sun sign tells you almost nothing about your natal chart. This notion that because you're a Libra, this and that and the other thing must be true of you -- that's nonsense. Not your fault, since it's been splashed through the media, but it's garbage. You need to understand your entire natal chart in order to get a sense of your strengths and weaknesses. If you can, find a good natal astrologer and get a full chart delineation done -- you'll be glad you did.