My only advice is make him salary efficient, whatever the skills. You can't go wrong. Basically, he needs to have close salaries for PG and SG positions, at least.
Meaning that HA,DR and Passing must be high enough, so your player is at verge of becoming a PG. Second, pump as much secondary skills as possible, IS, ID, SB. As for rebounding, just leave it at the starting level.
1. step: Figure out when to start training guard skills, so there is enough time to reach cap. For example, he can get capped being trained 22y-27y
2.step: Train big man skills 18y-21y
For fine tuning the skills, depends on the starting skillset and what build you like, or want to try out. But salary efficient can't be wrong, whatever skill distribution you choose.