It looks like the guy you're talking about is 20 years old. To get 10 pops in guard skills and10 pops in inside skills, I would expect it to take until partway through his 23 yo season. I think IS and ID train pretty slowly on 6' players, and the RB and SB are low enough that that will slow IS/ID down as well. If you can get him in as a SF and train JS (or 1v1) for Forwards when you're doing JS/DR/HA training it might speed it up by getting you some of the IS pops.
I looked at a potential/cap calculator that uses Joseph Ka's formula and it looks like you'd have room to train him up like that, plus do the OD/PA/JR training you were talking about before he capped.