The only thing I added to the already great design is the option to generate a concentric funnel. This way You can spare some material on height, btw.

V3: I have just realized that below a certain base diameter the shaft guide itself prevents the pepper to get into the grinder. So I added a new option to remove the shaft guide if necessary.

V4: Replaced Checkboxes with Yes/No options so they show up in the customizer.

(For some reason I cannot see the Concentric option in Customizer, so You may need to download and use the .SCAD file to exploit it.)