Sadly, SB and JR are the keys of this kind of lineup but also the fewest ones people would like to train
(36936952) JR of a guard, SB of a big 
I need two seasons to finish him. Unfortunately he was 19 y/o at his draft... But hrudey is also one of us freaks ;) who trains such guys. I'm eager to see what he can do with his players.
Well, if this season is any indication, my best-case scenario in a few seasons is winning games 35-33. I've played 3-2 pretty much every game, with the C position always being manned by a second-season trainee (two are 20, one 19), and the PF starter is far from superb. Plus my guards' OD is not really excellent either. So naturally I'm still leading the league in points allowed and that's even with actually playing fast offenses pretty much all the time.
I'm still not sure if the big men will ever get any JR or even JS training for me. I may try to mix in some seasons of outside shooting for PF/C when I'm close to cap levels, just because I refuse to add IS or DR or PA. If only projects like this didn't take actual years, I might someday try to do this without keeping one draftee in each group of three trainees despite them not being nearly as good as the other two trainees for what I want to do.