what you are asking for already exists. 
how to use 8" guns:
 get in a gun position. 
 open clipboard, zoom in, click on target. 
 press shift-Q to enable Land Mode.
 zoom.
 if you cant see the target, hit F8 and slew the sight view so you can.
 fire.
 observe impact and readjust fire.
I was tempted to say RTFM but the "manual" is out of date and wont help you. in fact the help system for AH is a complete dogs dinner, most of the really useful stuff is hidden away on the trainers pages.