Awesome. I've wondered about practical applications of MBTI, advertising seems perfect.
My suggestion, to overcome some of your questions, is to study the functions and their relation to each other. There is some good reading to be found strewn about. Some people like to focus on the type descriptions (or solely the letters themselves), which are good too, but I find that to be more like reading the answer and agreeing than knowing the questions themselves.
At any rate, good luck with your search. I'd be glad to answer any questions you have to the best of my ability.