First thing I'd suggest is KM. But that's already done.

Certainly a slow fade away, while hitting an advancing enemy will give you the best range advantage, but you can't pick and choose the optimium arrangement during battle at any given moment.

You need to know every 5 degree range set top to bottom on your guns, then you'll know the diffference between 31 and 32 degrees within a click or two on your guidelines. 

I rarely adjust my degree settings during the North/south stroll; but will move in or out towards the enemy to bring my drop zone onto the target, fire, then get out of enemy range ASAP.

But incoming ships (CLs, SS, pesky FF), require annihilation promptly, as they are much more a threat as super scouts, exposing you to the enemy BBs, than their noise making guns; so you need to know your 0-10 numbers without hesitation.  

 Certainly the more familiar you become with your guns, you'll have them dialed in and know their range and impact cluster.

Well KM suffers from jumping range on H39 and bad spread.

First now what your range "should be:

http://fm.en.kupaisky.com/Community/Forum/View.aspx?num=7691&searchtype=0&pagecount=0&searchvalue=&sort=5&category=A04&page1=1

make your guidelines so they match the middle landing shot (the one line a bit before a white dot.

Then the most crucial thing is to learn how to sling. infact as soon as u hit H44 u will need to master it other wise the 1mm range advantage is nothing, but when u have mastered it even this 1mm combined with the hugh distance between front and rear gun allow u to have a really effective range advantage even against a L2. in fact H44 range and L2 nearly match but by the gunplacement u can get a hugh advantage. To use that is what makes a good KM driver and what makes some other noobs. Furthermore keep in mind KM is mend to be driven a bit offensive. especially with H44 constantly engage someone. Your task is to push (not rush!) and for that task its a perfect ship. Furthermore with KM use your AA and always have a overview about whats going on... with H39 u can be lucky and get away when u were ctached off guard but with H44 it often means death.

Regarding knowing your angels: 99% of the time u should be playing at 34 degrees beside that occasionally u will need 32,30 and 20degrees.

Hit the space bar harder for more range.

So I found this image while searching about how to slingshot. The way I understand it is to just fire when your guns are nearest the enemy ship, which is usually when you rotate as you run away from the enemy. That way part of your ship length is added to your normal gun range. See the 3rd diagram.

where I read it:

http://leviathanfleet.proboards.com/index.cgi?action=display&board=open&thread=200&page=1