Get a friend and use dual ganondorfs. One of you needs to jump up and use down c stick on the bag. The other ganondorf should use his kick since the bag will stay down due to the other ganondorf. Repeat this process until about 1.5 seconds. At that point both of you should move to the left of the bag and at 1 second or just after hi the neutral b button WITHOUT THE BAT. As long as you have the bag above 220% ( which is easy, I've seen people get over 400% ) you'll hit 3800 ft easy.