Um, if you're dedicated to making him a SF, he may develop a bit too late to make the U21 NT, but he can still be an fantastic player.
If that's the route you'd like to take, just train JR and OD for the rest of this season.
8 weeks OD and 6 weeks JR.
Then next season, train jump shot and passing, split 8/6.
When he's 20, you can smash some inside skills, mainly ID and IS.
When he's 21 again, just train OD and JS/One on One for the season.
At 22 you can either polish his passing/jr, or focus a bit more on his inside skills.