I absolutely adore the Mutsuki now, it's probably my favourite ship at the moment. This is my setup:
I have the C hull, 10km torps and the AA guns and steering gears modifications.
My commander skills are:
Basic Firing Training and Situation Awareness. Torpedo Armament Expertise Vigilance Advanced Firing Training
I get 40% extra range for the AA guns (they start shooting at 7km or so), turn the AA guns off (P on keyboard) to go into "stealth mode" With the modification and commander skills you should get an AA rating of 37, which is pretty decent. If your escorting your battleships in a match with some carrier action going on you can expect to get between 5-15 plane kills, can be more or less depending on the individual match and playstyle you adopt. But the AA is good enough to help protect your teammates and fend off pesky spotters.
You lose two guns with the C hull but the fire rate and turn speed make up for that. They are also very accurate and they seem to be balanced to have a higher chance of setting fires in my experience, I'll set as many fires with the occasional potshot in my Mutsuki as I do from spamming HE in the Farragut! You'll get about a 9km range with the guns if you get the Advanced Firing Training skill, with is good enough to allow you to take the odd shot at the enemy when the situation allows and still be able to maneuver away quite safely. I highly recommend the steering gears modification, It really allows you turn very quickly which is essential to evade and dodge, as well as to bring the torp tubes to face the enemy.
A typical match with 1/2 carriers on the enemy team goes like this; You want to position yourself in front of your BBs and move with them, shooting any planes that get near and acting as torpedo early warning in case of long range attacks from the enemy DDs. Keep close to them and shoot torps out towards any ships that are heading towards or across from you. The twin guns are quite effective at incapacitating any DD that gets close, allowing your team to finish them easily. As the match progresses and the enemy ranks of ships and planes have been thinned out you can engage stealth mode and break away to hunt battleships and perhaps a carrier or two. Obviously don't leave your BBs or CVs defenceless if there are DDs lurking nearby. A Mutsuki set up like this is quite handy at hunting CVs as you can shoot down plenty of their bombers they will send at you as you get within 3km to deliver a killing blow. Save your smoke for hiding your team while capping or to protect your CV from enemy fire, if I use it as self protection it's usually a last resort when something's gone wrong or I've been ambushed.
That's what works really well for me anyway, it takes a little while to adapt to coming from the Minekaze and I find it's necessary to be much more accurate with the torps due to the slower reload. It's important to learn which way an enemy player is likely to turn and shorten/lengthen the firing angle accordingly. Playing as the different ship classes regularly gives you a good advantage, as you can put yourself in their shoes and make an educated guess as to how they will turn. The predicted intercept guide for the torpedos should only serve as an indicator of where the intercept will be at their current speed. As the reload is much slower, you'll want to make every salvo count.
Best of luck out there and happy hunting!
