If you want to maximize the benefit of SF training I highly recommend doing Inside Defense (C) at least until All Star Break, and then follow that up with some 1 on 1 Forwards to gain skill in your Driving/Inside Shot/Jump Shot/Handling. Do that until he is close to turning 20 and then jack up his OD with Pressure (PG). I followed that plan and was able to get +52 Skill Points on my former U21 player last season (Lorenzo Shipman) who also played dominantly in my Utopia league.
Doing the Inside D first gets it up to an adequate level to where he won't be a liability and when you get to Outside Def. training he'll become a superb defender which is difficult for even higher league SFs.
3 Time NBBA Champion. Certified Trainer. Mentor. Have any questions? Feel free to shoot me a BB-Mail!