To take full advantage of training this guy, you'd have to revamp your roster. If I had your roster, I'd sell a few of your older guards and purchase two 18-19 year old draftees. Look for star-all star potential(maybe perennial all star), and don't spend more than 100k on any player. Look for two things: (1) at least mediocre OD and (2) height of no more than 6'3". Buy an advanced trainer with these purchases.
Then, single position train pressure until Walter has strong OD. This will allow you to play him in league games. From there, you can go a couple of different ways: 1v1 forwards, passing, you may have to throw in some jump shot training as well. That pitiful JS is pretty ugly.