The best advice i can give you as a new H44 driver is to not get in over your head, play keep away early on and use your AA to it's best effect if you have AA gunners.  Zig Zag as much as possible when you do end up in a fight and keep the enemy confused, the less predictable your movement the better for you and more chances your enemy will make a mistake. 

Always be aware of your position on the map and make sure if you see any subs to stay very far away from them, the H44 has a massive hitbox and torps love it because of that fact.  Use your mass of scouts and AA to ensure some scouting and keeping your enemy blind.  Do what you can and make your shots count.

Also learning your lower angles in a test battle would be a good idea so in case your rushed you can at least figure the angles between 37 and 20 easier.  Once you are able to do that the h44 can be rather nastey.  Stick to the dual 20" guns don't bother with the 110 guns on the 44.

Since your now in a big shiny BB5 now is when you should be on the south side of the map every match or nearly every match.   If enough bb5's are south you can go north but only when about 2-3 bb5's are already south on your side and or a BB6 with a bb5 or 2 backing it up.  Least thats my rule of thumb when i play my bb5's, too many big ships in one area can lead to a lot of crossing in a GB environment.

guy above me summed it up very well. h44 is the best aa ship in game hands down. learn ur aa angles an shoot the scouts down. and u will be king of the ocean. keep ur distance. h44 is a great ship for keeping enemy at a distance. but once rushed run. ur no UK. and also beware of UK armored ships. always load 1 salvo of AP shells. h44 is a great chase me ship. u want to rush u picked the wrong nation. if u don't have aa gunners then get some. anyone playing km with no aa is a retard

So, your Job is to do AA duties for others BB, because most on players don´t use AA at all, and complain all the time about camping scouts...

Any way, your spread with LVL100 guns won´t be great everm don´t panic about that.

As KM player patience is one of most values things that have to learn.
Zigzag, kill everything on the air and look for the right moment to attack.

Every BB that goes in your guns range, shoot him.

If your ENG are beloew 105, use 3 HE and 1 AP bind. Also, use the 4.1 AA, golden angle 32-33. Wait less ans cant hold a LOT more AA ammo.

In WaW enter when you reach 110 and use the same tactic. 

i had not meant slingshotting as not everyone does slingshot, if you do nd can good for you if not you can still zigzag to avoid incoming fire.  Also the h44 does require patience when you wish to find a opportunity to move in and be aggressive, if you commit too far and out pace your back-up your more than likely dead.

On some rare cases you won't die but more than likely you have a very high chance of such.  Also i do not fully agree with your L2 needing to really wait, if you fire just a second or so too late in the h44 a L2 turning in and rushing you can be a disaster simply because it has a very very small hitbox when it turns in.

The h44 does not have a very good ability to drop a lot of shells *and for that matter most BB5's* on a rushing L2.   So for that play keep away and fire on the rusher while falling back, if you have support you can hopefully bait the L2 into range of your other teammmates if they are paying attention.

If you do not have support and you are the last on your team / in a 1v1 situation with the L2 you can either continue to fall back and fire or counter rush, only counter rush if you know your lower angles and have plenty of OH left. 

Do not counter in a straight line again make sure to weave back and forth a little to try to minimize your ships hitbox and keep it moving, the less shells that hit you the better chance you will survive so long as you hit more than the other guy does.

Also as said before make sure to use your AA to it's fullest, snipe scouts and make sure to go around fighter waves with your scout as manipulating your scout is a key factor in playing a H44.  Plus german AA is good for killing bomber waves if any try to head your way.

I play it that aggressive and i do very fine whith that. Though i have to admit a lvl 120 crew allows a lot more aggressive playstyle compared to at lvl but still, H44 is a ship tht has to be at the frontline always. Even L2 are easy to controll. When you do the slinging right you are still far away enough to run a lot before they get you and when they are close enough best you can do is a counter rush.

Well i moght not be the best H44 player but i guess i can say something about KM AA.

KM40 are the best gun overall and they can hold a decent ammount of ammo on the smaller T slots on H44.

However there are alternatives.
The 4.1" (lvl 55 guns) can hold a crapton of ammo for the price of slightely smaller firepower and range.
The loss is minimal since 4.1" does 14 less damage (84 firepower) and has a 0.5 degree higher GA (a difference you won't even see unless you fire the guns next to each other.
They also mix well enough with KM40s (but not nearly as well as 4.7" with 6.1" on Yamato).

Then there are the 3.46"
Used mostly on smaller ships with worse AA gunners due to their innate reloading speed can turn into skycleaners when on a higher level ship. They do however have a noticably smaller range (36 degree GA) compared to KM40 but mixed with NFfixer they turn any ship into a no fly zone... basically they're better against bombers and camping fighters but worse when it comes to well managed scouts.

As for tactics...

1 - Don't get rushed. H44 is bad against rushes.
2 - Slingshot all the time.
3 - Remember that south gets a range advantage against north and it adds up with KM innate range advantage.
4 - Don't rush unless the enemy is blind since H44 is ridiculously fragile.
5 - If the enemy is running follow them slowly but don't get into their range unless they're blind. Just let them run out of space to fall back.

I skipped all the KM bbs... Went from Europa straight to H44 and I have got to say... It's the most amazing BB I have played.

Eariler today I 2 shot a Charlamenge... though I watched a monty 1 shot a nebraska. Made me feel small.