Since a lot of people seem to dislike the idea of an inside/outside defence training, how about an inside/outside scoring one. This would mean you could train your player say two seasons training at PG for OD/PA, then one at C for ID/RB, then you would be able to play him at SF to train one on one for DR/HA, Jumpshot for JS, and inside/outside for IS/JR.
This would allow you to get your player, and focus on his defence early on, as a lot of managers do anyway. Then at 21 you could actually play him at SF to get all his other skills up. In my opinion this would be a good compromise for both sides of the argument, as you would still have to train him out of position, but you would get him into his preferred position sooner.