Im currently using this mod with FU,Enchanted Storage and Even Larger Bags mod. Just needed few edit and one extra mod, also maybe must play above 720p[1440x900 or above] to get it working properly. (Haven't test it on lower, sorry)

1.You need to change the gap size.Follow the Customization Instructions
https://community.playstarbound.com/resources/container-ui-tweak.3777/
-note- interface.config.patch replace "/displayCenteredWindowGap" to "/bringAdjacentWindowGap"
Set the Value to 0 or any number to your liking.[personally prefer 10]

Example:-
[
{
"op": "replace",
"path": "/bringAdjacentWindowGap",
"value": 10
}
]


2.Install UI Scaling Mod
https://community.playstarbound.com/resources/ui-scale.2596/

Edit-1
you need to drag your inventory to very edge to the left.
Example:-watch this short vid i uploaded
https://drive.google.com/open?id=1xh58R88nAG03Gg6VF13hepASBW7UHeLe
playing on 1600x900 resoluton.


Thats about it, Im not sure if this any help for everyone. Well good luck, I guess.