Clodius
I found Eureka Grinders do retain grinds, even when used as single doser, I found it would clog the anti static bars in the chute if used with bellows. So there was always a chance of variation in weight output, as a load of retained grinds could be randomly unblocked from the chute at any point.
I think they are great grinders when used with the hopper, and just accepted that there will be variation of the first shot when compared to the second, third etc.
Then again, even with my niche duo, using bellows between each shot, on my ACS Vesuvius there is usually 3 seconds difference between shot 1 and shot 2. Shot 1 taking 3 seconds longer.
I put it down to group temp being hotter/cooler at the start, as my niche is incredibly clean with regards to retention.