Warrior General Games

I'm an owner who's trying to get his backup QB some xp in a way that actually helps the team. (ie: giving the starter a rest only when his productivity is dropping to the point where it's worth it). I would "rate" my backup QB as 75% as effective as the starter.

So far, everything I've tried has resulted in either the backup getting more time than I want, playing in critical situations, or not playing at all.

Any suggestions on how to optimize my QBs?

Thanks!
Barth