Personaly, i prefer a balanced team, in that way everyone has the same role, and if one has a bad game or gets injured you will not get a big impact on him missing a few games.
In therms of training, i am now developing SG and PG, i managed to buy them with similar stats, better at defending and passing with great secundáries, my strategie is to have good inside players for now, and play the ball inside. In this way my big men will score a lot of points and my outside guys dry the other team outside game. But this is my idea of the game, everyone has their own idea i believe