the only thing you can really do on a screen is manually defend it yourself (unless your DL decides to magically recognize it.... not sure what determines that, i have ngata who is high at prc and awr and he didn't recognize any of them). i dont mind manually defending them but the problem is he will often times lineup the slot receiver on the opposite side of the screen, which is where i would typically be defending watching for julio and then i can't make it back over to the other side.
also doesn't matter if you call contain really. on his last drive i already knew a screen was coming, called contain, and nothing happened, i had to make the play.