Off course not many teams have a leader 16 or more. For you a (preferably two) leader with 9 or 10 is sufficient, also because you can find them on the TL and are cheap. Just look at 30+ riders and check their LS. Off course you have to set your objectives at every race, go for stage wins or the GC.
I have a 22, a 15 and a 5 LS, I try to use the 5 as much I can because he is the youngest ofcourse he isnt really suited for (big) tours. So most of the time I pick him for one-day-races and ofcourse all U21.
I also prefer using the 15 for tours over the 22, they are the same age but while the highest already gives enough tactical option the other still can improve, so using the 22 a lot seems a bit like a waste of valuable leadership experience.
What I try to tell is that you have to choose wisely , you can buy a older leader with 10 or higher Leadership that gives you some options in the tactics, (and like rarau says only when he starts getting around 20 LS you will enjoy (almost) complete freedom of tactical options) but using him also means wasting valuable experience for the man that could be your future leader.