Based on the excellent work of diomedet, I had some ideas to make it more useful to me.
As per their model, this is compatible with the Army Painter Hydro Pack, although I include STEP file for modification to another system if desired.
Due to awkward size, there is a bit of wasted space to make it fit the grid. For my version I thought adding a bit of brush storage attempts to aid in usefullness.
The other main thing I wanted to change was to make it more compatible with the system when the lid is on, so I modified the height to work when complete, as well as adding the upper surface to allow use with other parts.
The final addition is a grid lid, which seemed like an obvious addition to extend the usefullness, allowing paintbrushes, paints etc. to be stored on top, reducing space usage.
Printable without supports. If you have any problems, please let me know.