Sorry for double posting but I think this need a separate post.
Here's my custom difficulty settings.
1) DARKER NIGHTS
Make the game darker than vanilla. Makes travelling at night extremely dangerous. Almost 0% visibility if you're not using Pibpoy lights at night. Best paired with
Realistic Lights.
Link:
Darker Nights- http://www.nexusmods.com/fallout4/mods/191/?
2) ARBITRATION
A. Better Combat AI
-Made AI (including companions) attack things all the time instead of waiting to be shot half the time (wildlife, power armor, and some special NPCs left untouched).
-Made ranged AI focus on flanking (companions focus on dueling to protect you).
-Ranged AI will flank, circle, and fall back more when in close range. I should note that I have witnessed falling back, but I can't vouch for the efficacy of adjusting the close range flanking and circling. Things "seem" to be better with these adjusted. Falling back is important as it keeps them from advancing to the point of idiotic suicidal.
-Increased odds of strafing for ranged AI.
B. Stealth Overhaul (Not main "Stealth Overhaul). I used the optional one. Here's the description)
-Sound impact on stealth greatly reduced (less "what was that" from people 40 ft away).
-The farther away you are the less likely you'll be spotted.
-Longer Stealth Search Time.
-Reduced indoors light bonus to match outdoors - more detectable.
C. Molotov Cocktails Fix
-No longer kill by explosion, but by immolation.
D. Better Fall Damage
-Reduced fall damage
-Greatly increased fall leg damage
-Can only survive up to 3 floors.
-The Adamantium Perk doesn't affect fall damage in any of the fallout games. This file fixes that for my fall damage mod. Use for rank 1,2, and 3 of the perk.
Link:
http://www.nexusmods.com/fallout4/mods/2037/?tab=1&navtag=http://www.nexusmods.com/fallout4/ajax/moddescription/?id=2037&preview=&pUp=1
3) DEADLY RADSTORMS
4) HARSHER COMMONWEALTH
A. Combat change
Combat.esp
-VATS max engaging distance is reduced.
-NPC HP increased especially high level NPC.
-More devastating explosives.
-Enhanced strong enemy (I.e Sentry bot, Deathclaw, behemoth...)
-Weapon adjusting
-Max damage reductions are adjusted.
B. Tempo change
Tempo reverse.esp
-You gain less exp when you play harder difficulty
-Legendary item drop rates decrease with difficulty.
-Harder lock picking and speech gives you more exp.
Tempo slow option.esp
-No exp from crafting
Tempo marathon option.esp
-No exp from crafting
-Increased required exp for level up
-Increased new discovery exp
C. SPECIAL & Perk & Companion Adjustment
S.P.E.C.I.A.L.esp
-Base carry weight reduced and carry weight per strength increased.
-Base action point reduced and AP per agility increased.
-Hard speech is affected by charisma than vanilla.
-Now Level HP bonus is determined by END only.
-PER has more effect on VATS.
Perk.esp
-Some Perks are adjusted. No NERF
D.Economy
Economy.esp
-Civilian has more item especially for the rich.
-Now Workshop gives you less water.
E. Hardcore Mod
-Hardcore.esp
-Healing from food reduced
-If food have special ability, they enhanced.
-Bobby pin has 0.02 lbs weight
-Cap has 0.01 lbs weight.
F. Monster Leveling
Nightmare.esp
-Minimum and Maximum level of Every Encounter is adjusted.
-Min : 30~31
-Max : 61~99
-Warning : I recommend if your level under 25, don't use it.
Link:
http://www.nexusmods.com/fallout4/mods/1295/?
5) LESS LOOT AND AMMO
A. Less Legendary Items
-The chance of drop legendary items is at 50%. The chance of appearance legendary enemies is unchanged.
B. Less Settlement Resources
-Reduces the amount of resources from settlement production by 50% from initial production.
C. Less Flora Outcomes
-Harvested crops in your settlements regrow after 14 days. The chance to harvest wild fruits and flowers is at 50%.
D. Harder Expansion of Settlements
-Resources needed to build defense, energy production and water production objects increased 2x. Some objects have increased perk requirements (Science and Gun Nut).
Link:
http://www.nexusmods.com/fallout4/mods/2593/?tab=1&navtag=http://www.nexusmods.com/fallout4/ajax/moddescription/?id=2593&preview=&pUp=1
6) REAL WORLD DAMAGES
-This mod attempts to balance and increase the damage model of the game by editing variables, body part multipliers, and eventually explosion and weapon data. Perks may be modified later to prevent silly modifiers that unbalance the damage model.
-This mod dynamically increases the damage to player and NPCs alike via their creature type and locational hit. Biological creatures are easier to kill, including yourself, while robots are generally harder to kill than humans. (But still easier than vanilla robots)
-The damage is amplified by damage modifiers on the individual body parts of the creature you hit, so there is no flat modifier, but generally you can see an increase of about three times the effective damage on human creatures.
-Armor can only stop a portion of the damage taken, and while power armor can save your skin, it does not make you invincible like vanilla. Power Armor will effectively make you take 50% damage. Lighter armor will only protect in a 5-25% range. You will still notice a difference in wearing power armor, and it can save your skin.
-Increases damage to player to a multiplier of 7x (optional that I added)
Link:
http://www.nexusmods.com/fallout4/mods/217/?tab=2&navtag=http://www.nexusmods.com/fallout4/ajax/modfiles/?id=217&pUp=1
7) CRIPPLED LIMBS FIX
8) TIMESCALE AND FAST TRAVEL ADJUSTMENT
9) HEAVY RAIN
10) MORE CRAPPY WEATHER
11) NO HUD
12) V.A.T.S. TWEAKS
I was about to disable the VATS in the game to make it more difficult but I realized some perks are connected to it. And its not a Fallout game if there's no VATS. So I just tweaked it.
A. Selecting target phase -Affects only selecting target phase.
-Targeting: Slow Mo =Faster than default. Similar to effect of Jet.
B. Combat Phase -Affects only combat phase.
-Combat: Slow Mo =Similar to effect of Jet. Doesn't affect critical shots and Kill Cam.
C. Combat Phase Rate of Fire -- Affects rate of fire in combat phase.
-Fire Rate: Vanilla -40 =Player shoots 40% faster. Same time settings as default V.A.T.S.
D. VATSTweaks: Hit Chance Rebalance -Hit Chance will be less affected by the distance and more by perception.
-Didn't clicked. Still set to default.
E. VATSTweaks: Critical Hit Bar -Determines how quickly filled critical bar.
(No way to set it to default so I chose the nearest to the default settings)
-Critical Hit Bar -x1.5 =It changes the basic value, so 3x doesn't mean that bar will be filled 3 times faster.
F. VATSTweaks: Hit Chance -Increase chance to hit in VATS.
(Also no way to set to default)
-Hit Chance -x1.1 =Increase hit-chance for every body part in V.A.T.S. If hit-chance for torso was 50% by default, then "Hit Chance - x1.5" will set it to 75%.
G. VATSTweaks: Engage Distance -Increases or decreases the distance from which you can target NPCs.
-Distance -x0.5 =Distance set to 2500 (default 5000)
Link:
http://www.nexusmods.com/fallout4/mods/1064/?tab=1&navtag=http://www.nexusmods.com/fallout4/ajax/moddescription/?id=1064&preview=&pUp=1
OPTIONAL
13) HIGH LEVEL SCALE
As suggested by CoolColJ. It'll be just an option for now as I will start a new game. Please see "note" below.
-Enemies are from 10 to 50 lvl higher than you.The game becomes very dangerous, we should be careful with any enemy.Need wait some time for cell reset.Existing monster or NPCs is not changed.
-Note by the author: Please install this mod after 40 LVL with modified weapons and armors.In the beginning is impossible to play!
As of now I don't see any conflicts in any mods after days testing and just wandering around. Just one thing that I noticed. I die a
"lot".

Just a note, I read in the Nexus Forums that
Darker Nights has its own "stealth settings" on it, said its members. I think it has something to do with the lighting or "when will the enemy see you" base on the darkness level. I checked the authors description but there's nothing. I didn't checked the posts though. But I prefer to Install it first before the others so that the
Arbitration can overwrite
Darker Nights settings, if there's any. Also the order of the list is also the install order. Please feel free to correct my install order as its still a work in progress. I'll post some screens later.