So your favorite mod has vanilla stash size and you need more! Here are the steps to merge the Stasher mod for greater loot holding capacity.
Pictures coming soon! 
1.) Download and install the following:
Mod of your choice lacking increased stash “YourMod”
2.) Prep Grim Dawn and the AssetManager modding tool.
Place YourMod along with the database and resources subfolders into your Grim Dawn/working directory.
3.) Using the ArchiveToolGUI:
Tools > Extract Database > YourMod.arz
Locate the extracted ‘records’ folder and copy to the working\YourMod\database folder.
Delete the existing YourMod.arz.
Copy/Paste the contents of stasher/database into YourMod/database.
No conflicts should exist.
4.) Rename YourMod/resources to YourMod/_resources
We are removing the existing arc files from the equation so AssetManager does not mess with them and only rebuilds the database arz file.
Open AM and 'BUILD" YourMod containing the added Stasher information.
5.) Delete the created YourMod/resource folder.
Rename YourMod/_resources back to YourMod/resources
6.) Using the ArchToolGUI :
Open > stasher v5/resources/ui.arc
Select all and extract.
Locate the extracted caravan folder and copy to YourMod/resources/ui/caravan. You will need to create the UI folder.
7.) Perform the following:
copy/paste Grimdawn/archivetool to YourMod/resources
copy/paste Grimdawn/zlibwapi.dll to YourMod/resources
Create a batch file at YourMod/resources with the following commands :
archivetool ui.arc -update . ui 6
pause
Execute batch process. If it was successful, it will show tex files added to UI.arc
8.) Load YourMod and play. You will need to repeat this process anytime you update YourMod.