I think the optimal swing, and the position that puts your body in, naturally produces a slight uppercut; especially on lower pitches. That's fine. When I see extreme tilt however, like with Dunn, or Edmonds, the angle of the bat greatly decreases the margin for error imo. And hitting is hard enough without lessening your chances.
I would drill home "down through the ball" as an important mental cue, of course making sure the kid understands it doesn't mean chop down. Chopping down and slicing the ball with backspin is completely different then staying through the ball and creating forceful backspin.
Maybe you or others on here, who have coached kids of all ages could tell me. How do you think the younger ones would respond? Would they understand the difference?
"I played the first game of a legion tournament wasted my senior year. Got hit in the balls by a grounder in the first inning and went 2-4 and puked in the cornfield behind the football stadium. That was the first and last time I ever did that." - bluesky5