I've had my Virtuoso several months and recommend the following settings (on a factory calibrated unit - you can recalibrate yourself if you need a wider range for espresso):
French press - 26 using Tom from Sweet Maria's method of slightly finer grind and a shorter steep (add water, sit 1 min, stir or swirl and wait 1.5 mins, done). A bit courser if you are steeping the standard 4 mins.
Chemex or vacuum (I use a Yama) - 20
Aeropress - 14
Espresso - for a pump driven, single boiler machine, start at 2 if beans are fresh (less than a week since roasting). As beans age, you'll need to go finer. You'll wish there was a setting between 2 and 1 (I may recalibrate at some point), but go to 1 when your shots come through too fast at 2 (and maybe tamp slightly lighter than normal). You can go to 0, if still too fast, but time to buy fresh beans at that point. Careful not to run the burrs with no beans at 0 - it may dull them. Target is a double shot (~14 to 18 g of ground, well tamped coffee) to come through in 20 to 26 seconds.
Enjoy your Virtuoso. I like mine, though my Ascaso Steel Uno Prof is asking for more options on the espresso end. I may do the recalibration or relegate Virtuoso to everything but espresso (and get a stepless grinder dedicated to espresso). That or put the Virtuoso on eBay and jump on a Rocky or THE NEW BARATZA VARIO.
Cheers from somewhere between DT Van and the Valley.
P.S. Stop in at the Wicked Cafe (one on 7th and Hemlock; also one downtown) for some Intelligentsia coffee. Black Cat espresso and a Rawandan for drip or press are great. Intelligentsia puts the roast date right on their labels. Wicked gets direct from Chicago 3 days after roasting, so look for anything around a week old or less. Happy drinking!