L.W.
I could be wrong, but I would think that aiming him down would potentially make it worse since diapers are designed to catch pee where it's normally aimed. Maybe switch him to big boy overnights in the smallest available size. Those are intended to hold what big kids put out. You can also put plastic training pants on him. I used those when I was potty training and they hold a decent amount. The only other thing is that you need to stop the nighttime bottle. It will rot his teeth. It happened to a friend of mine's daughter's teeth. It was awful. They had to be cut out and she then had no front teeth for three years. If you don't want to give that up, give him water.