[Vince, Pt. II]

So I've managed to get a few interesting players into the Youth Academy now, and I'm wondering what my training rotation should look like. How do I best rotate training so that the guys I'm interested in reach their potential?

Here are the players I'm mostly interested in:

Leslie Johnson (15 years, 81 days)
???/Weak Defending
???/Passable Winger
???/Inadequate Passing
Weak/Inadequate Scoring

Ben Switzer (16 years 51 days)
Inadequate/Passable Defending
???/Weak Playmaking

Hugh Parrish (16 years 72 days)
???/Solid Keeper

Akash Gibson (16 years 75 days)
Inadequate/Solid Scoring
Weak/Weak Passing (not maxed yet)

Milton Cid (16 years 84 days)
Inadequate/??? Keeper
(just pulled him, scout says Weak all-rounder)

Luis Arellano (17 years, 26 days)
???/Passable Defending

Unfortunately I don't think I'll be able to get any of the really interesting ones to Solid before they hit 17, but how do I maximize my potential return here?