I think basic cannons should have the ability to receive input values such as vertical height and horizontal width. The current method of mouse cursor aiming is very clunky, especially long range accuracy takes a long time to get right because the clock is a sensitive tool to use. In the heat of battle you cannot allow yourself to waste 30 seconds aiming cannon(s) in the right direction.

It would go as follows: Right click cannon with clock, type /aim and the cannon would configure itself to those coords.
Example: /aim 4 20