I took a look at your roster and I didn't really see a shooting guard that screams train me. If you're set at training outside shot and jump shot your best bet is PG and SG. Alfred Banzon is still a trainable player, Sidney Molon is the player I'm guessing you're training at SG just by looking at age and potential.
However I'd suggest, if you're not married to the notion of guard training, to focus training efforts on Porfirio Bondoc. MVP potential and still at a very trainable age (19) he could be a very strong player for you.