Train whatever the U21 Canada manager tells you to train. Personally I would try to get another 2 pops in OD and 1 in JR before working on passing. I seem to recall some claiming that height doesn't have as big an impact on PS training as things like OD and JR.
You definitely don't want him to be 6'7 and 20 and the U21 manager says he needs another 3-4 pops in OD. That's why I suggest you train whatever the U21 manager tells you to train.