I appreciate you featuring my IFHE Mogami replay in ranked Zath it's nice to be able to show to a more general audience what the purpose of the ship is and how it should be played especially in a setting where winning or losing doesn't affect only your win rate or stats but where you stand in ranked. So if you did notice that while I did not have a kill I did end up finishing that game at something like 140K damage and where I positioned myself was almost at the maximum range of my guns mainly for the purpose of trying to tank as much as possible without getting hit. The idea of the game is to be a distraction that forces the enemy team into a predicament where they have one of two options, ignore me and I slowly whittle down each ship one by one OR shoot me and generally miss or do an overpen or a pen worth of damage for a full broadside instead of shooting at my battleships or my destroyers. Also my main reason for picking Mogami over Atago was because I felt that in having a heal I was able to play a little bit more greedy which ended up with me getting punished heavily because I could take a massive hit but still heal back some of it which wasn't good in the long run. Also when comparing the damage per salvo between the Mogami's 15 155's to Atago's 10 203's you end up with a theoretical maximum salvo of 39K with the 155's to the 33K with the Atago's 203's for HE and theoretical maximum salvo of 49.5K with the 155's to the 47K with the Atago's 203's for AP so it is technically more damage either way with the main differences being that Atago retains better AP shell penetration at range and Mogami has to run IFHE to maintain the ability to pen 32mm sections of plating where Atago does not.
Ship module build that I ended up going with was:
Main Armaments Mod 1 because your turret armor is 25mm all around which means that they will likely be incapacitated ir not outright destroyed if you did not have MAM1 equipped
Damage Control System Mod 1 for the lower % chance of flooding and fire and the slight torpedo damage reduction (I did not find my engine or rudder getting knocked out consistently enough to not run DCSM1)
Main Battery Mod 2 for the turret rotation speed increase of 15% at the cost of a 5% longer reload, I opted for this instead of ASM1 because while it was nice to have a tighter cluster of shells I found myself unable to track targets in a turn which meant that I could not maintain my DPM due to my guns not being able to fire from not being able to keep up with the ship.
Steering Gears Mod 2 for the faster rudder shift allowed me to be able to kite much easier at mid range which meant that I took less damage overall when I was running and gunning and fighting and kiting.
Concealment Systems Mod 1 because the stealth is arguably more valuable than the double rudder shift just for the sake of being able to stay gun silent if you needed to in a bad spot or being able to sneak up into a better position without being caught as fast.
Captain skills that I ended up going with was:
Priority Target 1st to allow me to know how many people were looking at me (with the intention of killing me of course)
Expert Marksman 2nd to speed up her fairly bad turret traverse speed on the 155's
Demolition Expert 3rd to increase her fire chance and to offset the fire chance reduction of IFHE (which is helped out a lot by having 15 guns despite the fire chance not being as high as the 203's)
IFHE and Concealment Expert 4th (if you do not have a 14 point minimum captain to do this I suggest you get a 14 point captain then continue as both of these ARE VITAL to the success you can achieve with this setup) with IFHE being the ability to pen 32mm of plating like a 203mm gun can do and Concealment Expert to further boost your Japanese stealth which with full concealment gets down to 9.2km.
Adrenaline Rush 5th because you will take damage no matter what throughout the course of the match so lowering your reload time as your health depletes helps out with eliminating targets or outright winning the DPM war (also helps to offset the slight reload time increase of MBM2)
Preventive Maintenance 6th mainly to reduce the chance of incapacitation of all your modules (your guns, your torps, your engine/rudder, your AA mounts/secondaries)
18th and 19th point, this is where you can kind of spend the remainder 2 points on whatever you so choose as you are fairly limited in what you have left to choose from but I would go with Expert Loader and Direction Center for Catapult Aircraft, Expert Loader mainly because your 155's do reload faster than the 203's so at 10.5s before AR it would take 5.25s to switch to AP and Direction Center for double fighters or spotters in the sky for self defense recon purposes or for offensive spotting purposes. That's my mindset on it but again you can kinda choose what you'd like with the remaining 2 points.
Lastly the first screenshot that shows 171667 damage was the absolute highlight of my IFHE Mogami's career in ranked in Season 8 there were only 2 ships that I managed to get higher damage in a single match throughout the entire season but the satisfaction of being able to play a ship that most people associated with being "a useless member of the team" due to the poor performance that most people exhibited while playing her and when comparing her utilitarian purposes to another cruiser(s) (looking at you New Orleans and Chapayev) and successfully ranking out made it all worth it. The second and third screenshots shows my module setup and captain skills.
Note: It was also rather hilarious to shoot at DD's and watch up to 75% of their health evaporate from a single IFHE salvo if they didn't detonate outright.
Edit: Thanks again @Lord_Zath and @SeaRaptor00 for doing the commentary!