I have used a Vario for dual-use for many months now -- and I agree with you that it produces a lot of fines. I think the claim that it produces bimodal output at fine levels and unimodal output at coarse levels is somewhat true, but no more than most home grinders. To a certain extent bimodality at fine settings is just natural to the physics of bean breaking. While some burr designs will amplify or reduce this effect, the Vario does not magically become a bulk grinder at coarse settings. At typical filter coffee coarseness (around 800 microns) the Vario's output does not appear as clean as the bulk grinders to my eye or palate.
That being said, I find I am able to produce a pretty tasty morning cup with the Vario and Clever Coffee Dripper or pourover cone. After much experimentation with sifting, I eventually felt like most coffees did not ultimately benefit. Sifting produces a clean, tea-like cup almost every time, but often at the expense of aromatics, body, and sweetness.
There are a few things that can help mitigate the effects of fines / wide particle variance:
- Try clean washed coffees roasted to a light level (for example many single origins sold by Ecco), as the smaller particles do not impart much bitterness in this case
- Avoid excessive agitation to reduce overextraction of smaller particles. This also helps to leave fines suspended in the slurry rather than migrated out to where they block the filter
- Be precise with your brew recipes (using a scale) and adjust your pourover grind to "dial in" your coffee based on taste (aforementioned very light roast coffees prefer a finer setting in my experience)