I just move them by making the changes.

BIG steps, then LITTLE steps, then TINY steps.

BIG steps shows me the direction/angle that each change makes.
LITTLE steps move it closer to where I want/need them to be.
TINY steps are used to perfect the changes.

For me, it's all trial and error until I get it done. :-/

Note. If you ever find "any kind of utility for finding exact gun coordinates", let me know! It would be a great help with modding Weapon for FSX to each different aircraft. ;)