Other than the convenience mods such as building it into a bucket and adding a shroud to keep dust down, the more important mods will directly affect efficiency and consistency:
Replacing, or as I did, just loosening the outer plate's retaining pin so that plate can freely move.
Being sure the outer plate runs parallel to the static plate. It should do this automatically with the first achieved.
Adding washers to the two bolts holding the bracket so they may be fully tightened down. The bracket shouldn't move or loosen at all.
These small improvements will allow you to run the mill with the plates near touching. In practice, my plates do touch unless there's grain running through them to force them open.