From my experience the blow up hopper has some flaws the way Eureka made it:
It doesn't sit flush with the grinder, so you have air escaping through the mount, not to mention the chute to close them off.
For this i used tape to better seal the hopper:
Another issue is that there is no valve on the lid. So what happens, if you use the hopper during grinding, you're actually sucking ground coffee back towards the hopper. Fine grinds will also clog the grinder because of this.
I added a one way valve from one of those rocket hand pumps used in cleaning camera lens.
After these two changes single dosing works much better (around 0.1-0.2 gram retention) and i can grind very fine if needed, also with zero clumping.
Popcorning is non existent as well.
In use i press the bellows multiple times while the grinder is running.