In my opinion 10 players is the absolute minimum, 12 to 14 would be fine.
I had 30 once, and I trained free throws at that time. It was manageable and I had a very large group from which to choose for my games, making me near unpredictable for my opponents.
This could work for weaker teams who are succesfull and get much money by being succesfull in the lower divisions, but once you get up, the wages will become prety big and having more then 15 players will then only hurt...
Free throw training might be good for your team, since this can make you win or loose some of the games, but it won't bring you much money in the long run, so I won't recommend it as a profitmaker to train players.
That being said, I myself never used follow chart until 4th.
I mostly use let coach decide (for important games) or strictly follw chart (when I want to distribute minutes as good as possible, in scrimmages).
Depending on the diffrence between your players, and the positions you want them to play, it might be better to take: coach chooses from chart.
My players are prety balanced, and there's not too much diffrence between let's say my SF and SGs, so either spot I put them, my coach normally lets them play there.
I can imagine however that is you have a pure SG, and wants to have him play the SF, while you let your clearly SF play the SG, that your coach wil switch them if you let him decide freely, so IF you wnat to do that (for instance for training purpose) I think you might best tell him to pick from the chart, or if it REALY is important, and the result of the game is not, then tell him to strictly follow it...
They are not your friends; they dispise you. I am the only one you can count on. Trust me.