CafeNoir I’ve done a DIY single dose mod. I made it from aluminium sheets. The chute first didn’t have a detachable top but I cut it off so I can clean the inside better. With a detachable top its a lot easier to manufacture (need some muscle to origami the aluminium sheet to shape…)
The problems I have is some grounds are still left in the burr chamber, and some grinds left in the chute. For some reason my chute clogs up often even with spraying. My process is spray beans, put in chamber, start grinder, grind goes in cup, turn off, brush remaining grinds in chute and around chamber, turn the grinder back on then use a blower and bellows while its on to push remaining grinds in chamber out then rebrush at the end. This ensures 0 retention and more importantly for me because I hate mess, no messy grinds on my counter or in the chute and burr chamber. Maybe a bit overkill but it works very well albeit too many steps. I’m planning on making a new version of my SD mod but I’ve had no time for it.