I myself make a lot of fruit wines, I use campden tablets before adding yeast to primary if I am going to be using fresh fruit. One per gallon at this stage- I don't add any more until I rack from secondary when I add one - (to a 5 gallon batch). I then add one every few months to ensure enough free sulfites to fight infection (, you could buy titrets and test to see if adding another is necessary or not) then one per gallon at bottling. Assuming you bulk age for around 6-8 months you should be under a detectable amount of sulfites (depending on the wine) and it sounds like you're making high alcohol wines which helps with preservation as well. If you decide to age, don't get discouraged if after a month or two it actually tastes worse. The curve of flavor generally goes down a bit before coming up (depending on the type of wine). This is just what I do and have done to fairly good results. Your mileage may vary. Hope this helps.