also when in land or sea mode you can adjust you target by moving the controler, it will show you how much you have adjusted your position onscreen, i am not sure what mesurement they used feet meters yards ect, but if you zoom you map right in and (in land mode W) click on one edge of a field, fire then the other edge of the filed the adjusted range is around 900 (yards ? i assume)
If you want to take direct control of the gun press Q
this also works for the 5" guns but the have only around 10k range, you will know if your target is out of range because the guns elevation and bearing will not change when you click on the map.
Also if you use the 5" guns press your secondary ammunition selector (backspace for me) and you can switch between AA shells and HE shells
The AA shells have a proximity fuse and thats why the are so good at hitting buffs ect, cause you only have to get your shell NEAR the target...
I dont know how viable they are for use on building ect, but if you were to shell a filed with AA shels (5 inch only) then anyone taking off or landing NEAR your shell will have a bad day.