Steven, it’d be good to know how many producers truly add CO2 at bottling. Ulli Stein explained to me that a small percentage of CO2 is lost during the bottling process and the bottler can add the same amount back. Yet most wines which were properly vinified (that is, not tired) don’t need to be refreshened, as they have enought natural CO2.
As for pressure tanks, they are rarely used by top producers in the Mosel. Stefan Steinmetz of Günther Steinmetz in Brauneberg does one wine from the site of Geierslay with pressure tank.
Lars, maybe my above statement re adding CO2 is not justified by actual numbers. At some of the last few visits to wineries (mostly in Baden and Franken), I talked about the CO2 to the producers and some told me that they add some CO2 to give their basic wines some Fizz. I also notice that most basic level wines I drink have more fizz than the mid- or top-levels wines of the same estates. It may, however, be that I made wrong conclusions from those perceptions.