This thread brings up a lot of interesting points.
I believe that one of the first things you should consider doing is to make a list of the things that you think you do well already, then another list of the things that you think you do not do well.
If you published that list here on AZB, others might chime in to let you know how much or how little you do know about playing pool.
The list of the things you do not do well could bring in an awful lot of suggestions both good and bad.
While I believe there is value in taking pool lessons from an instructor, I feel that the instructor who teaches well and plays well is the one I would choose to move me to the next step.
That being said, if you were short on money and you were serious about improving your game and you would give feedback to this Main Forum, you could possibly get some of the finest information available anywhere. Don't be a bit surprised if you get a little doo-doo from the forum. It can happen with instructors as well.
I think once you think that you have the knowledge then you can be evaluated by a professional level coach or top flight instructor.
I suggest acquiring the knowledge that you don't have first, then see if you can execute on your own.
That thread could become the longest running thread in history.
Best of luck on your new journey.
JoeyA