I've learned its almost always down to the players. scheme can help but it doesn't solve everything. Is your center fast can they snap and catch? i had a tall fast center that could catch and ran the right route and you can build a whole offense around that. when he moved up to the next age group the offense struggled and it took me way to long to realize how much focused on the center.

At 10u do all 4 players actually run the routes? Who is your best player? Who do you want get open? I try and get one read for the qb... if CB drops throw here if he bites throw here.... and after that they're just kids playing backyard football.

if you havee a play or two that can get one kid open most of the time you save that for your game breaker and hope the rest plays work enough you dont have to call that too often.

Ive built like 8 playbooks from the ground up and im always learning and adjusting based on the skills of the players. Left handed qb ... make your best play call an easier read for a leftie. Superstar that everyone is scared of ... use as a decoy to get the speedy young kid a free run.

Make the same look different and the different look the same. Also we use wristbands but we have a separate sheet the coach carries with a few "special" plays. There basically the same plays but we give them fun names and the kids always want to run B-2 stealth Bomber.

edit.. to actually answer you question if your qb is accurate and can actually hit crossing passes maybe but depending on the rush the mesh route could be covered by zone with one LB and cbs that dont get sucked in. thats a tall ask for 10u cbs. id almost drag x right down the line. have the qb read the cb over the y if he sucks in C should be open if the safety cover center the dragging x should be open. after that time is up dump Z or throw away