It looks like you want to train centers, and you have quality trainees with the two that you just bought. With dedicated single-position training, you should be able to get those guys up to where they're mediocre division IV starters some time next season. Until then, you'll be underperforming at that spot and there's not a lot you can do about it (other than picking up some older guys and 2-position training,which will hurt you in the long run).
I would say that you have two young guards in Peterson and Sietes that are probably not receiving training and might be worth more to you on the Transfer List. I you'll be training the C position, I'd suggest picking up some older, trained-up players at PG/SG. Either that, or you could try something kooky and train them in RB/1v1/JS along with your C guys for a season or two. I think you'll end up weak on defense across all positions, if you do that, but it's up to you.
What I would do is hit the training on those C's hard, starting with ID so that they won't kill you when you're playing them 48 minutes a game. Look into buying some older guards with more skills. Expand your arena to at least 8000 seats and maybe play more base tactics on both offense and defense.