A simple elsfied mod that uses the creation kit to fix the vanilla armor clipping issues when sheathing 2 handed weapons to the back for both player and NPCs.

Should have minimal compatibility issues, install and uninstall whenever you want. 

Most testing is done on the male character and since both males and females share the same value, the female character may likely still have clipping issues; if I make the 2 handed weapons just far enough from the female character back, the 2 handed weapons will look like floating on the male character's back, vice versa. Due to the creation kit limitation, minor clipping for some armor is unavoidable (I can't move the weapons further past "4".)

For reference, below are the edit value of "weapon adjust" within the creation kit for vanilla skeleton meshs:

ArmorCompanionsCuirass (wolf armor) 0.40
ArmorIronCuirass (iron armor) 0.30
ArmorIronBandedCuirass (banded iron armor) 0.50
ArmorStuddedCuirass (Studded Armor) 0.50
ArmorHideCuirass (Hide Armor) 0.50
DLC2ArmorNordicHeavyCuirass (Nordic Carved Armor) 4.00
ArmorDaedricCuirass (Daedric Armor) 4.00
ArmorScaledCuirassB (Scaled Horn Armor) 2.00
ArmorScaledCuirass (Scaled Armor) 0.40
ArmorElvenCuirass (Elven Armor) 1.00
ArmorBanditCuirass1 (fur armor) 0.30
ArmorDraugrCuirass (ancient nord armor) 4.00
ccBGSSSE058_ArmorBladesCuirass (steel solider armor) 4.00
ArmorNightingaleCuirass (Nightingale armor) 2.00
ccBGSSSE059_ArmorBladesCuirass (Dragon Insulated armor) 4.00
ArmorDragonplateCuirass (Dragon plate armor) 4.00

Since XPMSSE Left Hand Sheath Rotation Fix provided by Simple Dual Sheath affects the distance between 2 haned wepon and plyaer, I've created a separete version for Simple Dual Sheath:

ArmorCompanionsCuirass (wolf armor) 0.00
ArmorIronCuirass (iron armor) 0.00
ArmorIronBandedCuirass (banded iron armor) 0.30
ArmorStuddedCuirass (Studded Armor) 0.30
ArmorHideCuirass (Hide Armor) 0.10
DLC2ArmorNordicHeavyCuirass (Nordic Carved Armor) 0.50
ArmorDaedricCuirass (Daedric Armor) 4.00
ArmorScaledCuirassB (Scaled Horn Armor) 4.00
ArmorScaledCuirass (Scaled Armor) 0.30
ArmorElvenCuirass (Elven Armor) 0.50
ArmorBanditCuirass1 (fur armor) 0.00
ArmorDraugrCuirass (ancient nord armor) 4.00
ccBGSSSE058_ArmorBladesCuirass (steel solider armor) 4.00
ArmorNightingaleCuirass (Nightingale armor) 0.20
ccBGSSSE059_ArmorBladesCuirass (Dragon Insulated armor) 4.00
ArmorDragonplateCuirass (Dragon plate armor) 4.00
ClothesMonkRobesHooded (Hooded Monk Robes) 4.00
ClothesNecromancerRobesHooded (Hooded Necromancer Robes) 4.00
ClothesRobesBlackHooded (Hooded Black Robes) 4.00
ClothesMonkRobes (Monk Robes) 0.10
ClothesMonkRobesColorBrownHooded (Hooded Brown Robes) 4.00
ClothesMonkRobesColorGreenHooded (Hooded Green Robes) 4.00
ClothesMonkRobesColorGreyHooded (Hooded Grey Robes) 4.00
ClothesMonkRobesColorRedHooded (Hooded Red Robes) 4.00
ClothesMythicDawnRobes (Mythic Dawn Robes) 0.25
TemplateClothesRobesMageMaster (Master Robes) 0.25
Archmage's Robes (ClothesMGRobesArchmage1Hooded) 4.00
DLC2ArmorStalhrimHeavyCuirass (Stalhrim Armor) 4.00
ClothesUlfric (Ulfric's Clothes) 4.00
TemplateClothesMageRobesApprenticeHooded (Hooded Mage Robes) 0.80
ccBGSSSE051_ArmorDaedricMailCuirass (Daedric Mail) 4.00
ccMTYSSE001_ArmorKOTNCuirass (Cuirass of the Crusader) 0.00
ccMTYSSE001_ArmorKOTNCuirassReforged (Reforged Cuirass of the Crusader) 0.30
DLC2ArmorBonemoldCuirassGuard (Bonemold Guard Armor) 4.00
DLC2ArmorBonemoldCuirassVariant01 (Bonemold Pauldron Armor) 4.00
DLC2ArmorBonemoldCuirassVariant02 (Bonemold Armor) 4.00
DLC2ArmorChitinLightCuirass (Chitin Armor) 0.25
DLC2MoragTongCuirass (Morag Tong Armor) 0.25

Some armor might be left out, let me know and I might fix it. 

This file is originally made to accompany my Skyrim Collection.

To learn how to do it on your own:
https://www.youtube.com/watch?v=g1xQq1DOynY

Fix the creation kit multiple masters bugs:
https://www.nexusmods.com/skyrimspecialedition/mods/2786

To learn how to elsfied:
https://www.youtube.com/watch?v=MFwTU3XbIFk