44 defense for middle school team-how much should I put in?

Coach,
That is a very unique situation for you to be in, and a great one I might add! You know the boss of the program, you played for him and are familiar with his complete system, etc. Thats great!
I would suggest that you begin with the base package ( if the ball comes to you, if it goes away, etc" and make certain each player knows his assignments in your base package. THEN ACCORDING TO YOUR PLAYERS ABILITY TO DO WHAT I CALL " ABSORB AND EXECUTE" (HOW MUCH CAN THEY HANDLE MENTALLY AND PHYSICALLY) START ADDING THE PERIPHERALS. You will know when enough is enough by the results being obtained. Some kids in that age range, you can do a lot with, others not quite so much.
Just always be cognizant of the fact the system is built around the players ability, not the other way around. With your enthusiasm and desire to succeed at coaching, you will be just fine. Good luck in your new assignment!

Coach Easton