You have gotten some good suggestions here, but the best one I can offer is to consider another option. You can spend 6 months with one person, or you can spend a week with 24 different instructors, and get access to a much broader range of information. My personal goal is to spend time with as many different instructors as I possibly can.
RandyG, Scott Lee, Stan, Tony, Rufus, Bob Jewett, Jerry Powers, Grady, Mark, Blackjack and dozens more (I suppose you could even add me to the list if you wanted to.)
Just think of all you could learn spending time with all of those great instructors. Why limit yourself to just one?
I would take that 6 months and go learn from as many different instructors as I possibly could. If you learned something helpful from only half of them, you would probably still come out ahead.
Just another idea to consider.
Steve
I think your idea is pretty good but I would add that by doing this, going to see a bunch of instructors, find the one that you feel the most comfortable with and who you understand the best and stay with that instructor for a longer period.
Another thing, just because someone is a great player it doesn't make them a great instructor. And, the best instructor may not be the best instructor for you. If you can't relate to him/her and don't understand them, that instructor won't be a good instructor for you.