What hrudey is saying - awesome team name by the way! - is that instead of having an entire team full of young players that need to be trained, make a decision. Either posts or guards. Can't be both. If you decide to train posts, sell your guards and buy some established veteran guards or vice versa. Doing both is negating the impact your lvl 5 trainer could be having.
What he said is absolutely spot on. Sure, it would be nice to be able to train everyone yourself and be able to build your own balanced team, but what will happen is that your players will train essentially half as fast as another team who is focused on bigs or guards, and they'll be able to shore up their non-training positions with veterans. You'll never catch up with them that way.
The thing to keep in mind also is that you really shouldn't buy young players with potential in non-training positions; if they're good enough to help your team right now, and have good potential, you'll probably pay a much heftier price than an older player with the same skill set. If they're not that good, and you're not training them, you're just throwing away money on someone who should be a borderline trainee for someone else. Your roster shows a distinct fascination with potential and youth, but what good does an 18yo guard with inadequate skills and allstar potential do for you? Take Nachum Ben-Yaacov - a guy that was discarded by a brand new team and has a salary under$3k. If you're training guards and his skills aren't too deficient, maybe you pick him up, but if you're training bigs there's no reason at all to waste time on him.
I would suggest that if you're going to stick with bigs, do that. Whether you want to primarily single position or double position train them, have enough trainees to make that work (2-3 for single position, 5-6 for two position). Look for some decent veteran players for the other positions and focus on the same trainees so that the investment in your trainer can pay dividends. You'll get there soon enough.