Using the grader: https://aquaponicslab.org/seedgrading/
Thingiverse link: https://www.thingiverse.com/thing:3911941

This tool has three parts:
-Places for spare parts for your dibbler and drop seeder to keep the spares organised and close by in the event of an accident.
-A mock slide plate with standard round holes in the front, put your seeds in and see what hole gives the results you want.
-If the round holes dont give great results, use the template on the rear of the tool to snap a picture and use inkscape or similar to get the hole shape that works. [beans for example].

Link for drop seeder: https://hackaday.io/project/168051-drop-