my first wild guess about training:
"a player will take around X weeks to pop up a skill, where X is the current level of that skill, considering that he has a level 10 coach and is training the minimum possible number of players."
(by "training the minimum possible number of players" I mean for example training only PG/SG for Jump Shot, or only PF/C for Rebounding)
this is just a first guess guys...