to reach good results with training SF he needs to be good at almost everything
the best thing to do is training him as a guard when you train JS, JR, pressure and other guard skiils, and as a forward when you train rebound, IS and other forward skills
dont train more than 2 positions, he will train too slow
i train guards, mainly point guards, it's recomended to train pressure, passing and one on one (the fastest progress training for me).
every once in a while work on his shooting, even thogh one on one works on both inside and outside shooting (quite slowly but still)
hope i've been helpful