So should I add gypsum?
I know everyone on this thread said less is more. Most of my reading states that I need some sulfate in my water. What do you guys think?
Whether you want sulfate or not is entirely up to you. I always recommend starting out low on sulfate and working up because a lot of brewers find that they like beer better with no or low sulfate. I'd start with just the chloride. Then when the beer is ready to drink taste some and then add a little gypsum in the glass. If you find the gypsum improves your enjoyment of the beer then brew it with some gypsum next time. Do the same thing with that beer until you find the gypsum amount that gives you the most enjoyable beer.
Lastly, if I am going to be using Distilled or RO water for all my brewing, would you buy an RO filter or just buy distilled at a grocery store?
That depends on how much brewing you are going to do, how far it is to the grocery store and how much they charge. Obviously if you intend to do this a lot the RO unit will be more convenient.