I have a Vario W+(purchased 2024), grinding medium roast for pour over. The hopper feeds all beans and no beans popcorn out of the hopper(20g dose). When using the stock hopper for single dose, a few beans would always hang up on the bottom lip of the hopper. I would then have to brush them down, while grinding.
The bellows is a perfect fit and clears the grinder with two or three puffs. I was retaining .5 to 1.0 grams before using the bellows. I think the item description of 0 to 0.2 grams of retention using the bellows is accurate.
Referencing the photos on the website item page. My hopper is different, having the printing seam lining up with the index mark/narrow lug. Index mark aligns with where the shutoff knob/lever is on the stock hopper. The photo with the hopper filled with beans on a scale is weird. On a Vario, just plan on leaving the hopper installed.