what sort of salary do you see him finishing at?
Do you want a player to keep for a while or sell for a profit? (if you sell for a profit you might be able to invest in a better trainee one day).
If you want to train him up to his potential and keep him i would suggest training his passing if you can, but it would mean training him and possibly your other trainees in positions where they dont play very well!
Also his JS will be important to train.
I think he'd be better to train as a centre than a PF
If you can only train inside skills this season then i would be tempted to increase IS, ID and REB and keeping them all equal.
In the mean time plan to switch to passing and jumpshot the following season or so.