Where do you set up?

I stay in the slot - protect the arms behind the body - trust my equipment.   If at the higher levels, the pitcher will pitch to the catcher.. foul balls will be away from you.  If at lower levels, and the pitcher misses in, then you may catch one.  Part of the job - in my opinion, but I was a catcher back in the day and an offensive lineman.  Taking a shot is in my blood.

I agree with NewUmpire - don't change where you set up. Stay in the slot. Trust that the pitcher isn't going to "miss" his spot by 18" in... If he missed by 9" in, then if the batter is any good, then he should hit that ball into far, far, away land...

Couple of other things to think about... Would the catcher's position allow for a ball to ever pass through the strike zone?  Are the catchers feet outside the catcher's box? You can quietly let the catcher know you cannot call a strike "out there". Some catchers are taught to set up outside every pitch - don't take the bait. The coach probably has taught his catcher where to be and is looking to "get" strikes that aren't. If you don't give in, the catcher will move back in to protect you.  Either that or you can toss the coach for arguing balls and strikes ;-) because he's not going to be happy after a while when his catcher's glove doesn't move, but it's a ball.