Clearly, one goal is to be understood by your listener(s). I think that everything else can be converted into 'will the listener(s) understand the same thing(s) (including degree of precision) that I mean, which provides a single quantity which can be maximized, even if it is nontrivial to measure.

Which leads me to realize that saying more than one thing at once is more of an art form than a communication method. I'm fine with communicating and arting at the same time, especially when they interfere constructively.