Still don't get the complete aversion to using small amounts of water to top-off. I could understand if the recipe was thin on fruit/grapes per gallon and a low ABV but it you plan ahead you can boost your concentrations and avoid the issues with adding a sugar/fermentation source to you wine during the aging process. (not with a kit wine perhaps) If a single bottle of wine (25.3 oz) is only 3% of a 6 gallon batch, a 3% addition of water to a batch shouldn't terribly dilute the batch either. Again when doing a kit wine or if the batch wasn't designed to be a little strong to begin with I certainly understand the issue with diluting. I use nothing but water (usually filtered or Distilled water to top off and I haven't had any issue with watered down wines.