HS uses hand signs.....T calls his own games for travel and Legion...
T will initiate a throw down to first (back pick) by putting his hand on his helmet like he was adjusting how it sits and the first baseman acknowledges by adjusting his hat with his hand on his brim.
Pitch outs are rare believe it or not. Keep your signal short and sweet and the catcher can wiggle 5 fingers or what ever you decide. If he wants the pitcher to step off, have your catcher call time out. Depending on your age it keeps the pitcher from mistakenly balking. Have him make a mound visit and tell him to adjust change up his hold. This is not something you want to teach a kid "in game". Teaching slide step and the art of pitching should be done in practice and if your pitcher gets tunnel vision and needs a reminder, just have the catcher do it. At a certain level, the catcher should be on top of that too...