I completely agree with the previous suggestion. Since he's only got perennial all-star potential I would stop training his guard skills immediately and concentrate on all his big man skills exclusively for the next couple of seasons (or longer) and attempt make him a SF in the long run.
There are 2 very important reasons for you to train his big man skills first. They will train slower so it's more important to get to them first, while he's young. It will be extremely frustrating and slow trying to get ID and IS pops out of a player his height when he gets to bet 23+ years old. This will also keep his salary down for the next couple of years while you're in a lower division.