I’ve done the same with my 10yo son. We hit in games from a 45 using neck slot. The 45 helps feel the stretch so much better. He is quicker and has some burst from the 45. Both help in using less arms. Even with that he still wants to push hands a little and work down and across. IMO the 45 and neck slot will help EVERY youth hitter. It will also make teaching the more mechanical swing movements much easier down the road (hopefully )When I coached my GD in 8U, she only practiced and hit out of a 45. She was often late to both load and swing. I'd front toss and tell her verbally when to swing. After some time , she figured out to swing on time. There is a lot to process and the journey is long. Now, at 14 we are still working on her swing mechanics.