Bulk aging is the best approach to wine making. Bottling per instructions almost always ends up with fine sediment in the bottles!!!!!! Sulfite it about every 4 months of aging but truly you should be measuring S02 levels and ph as sulfite is added accordingly to what your ph is. High ph #'s means your acid is lower this making it more tolerable for bacteria to grow which in turn means youll need more sulfite. If you dont have anything to measure these then you can wing it by adding about another 1/4 tsp after 4 months and then after that gradually work your way down on 4 month intervals like on the 8th month add about 3/16 of a tsp. Most likely doing this youll be on the higher side of sulfite levels but its better to be on the higher then lower or your wine will be in jeopardy.