heavyobjects wrote:
What is the proper altitude to do this?
If you select your bombs and then hold down A, you switch to automatic release mode. You'll know its working because as you get close to the target, the green vertical line that appears on your screen will have a marker moving slowly downwards.
Just keep A held down while lining up the crosshair with taps of the left/right trigger.
If you do all of those things right, the altitude doesn't really come into it.