Ibhave found that ez water always has me add too much. Over time I have dialed my additions in as follows- keep in mind I use 100% RO water(clean slate):
IPA grain bill and salt additions:
14.25# 2row
C20 10oz
Carapils 10oz
4.8g mash(I only add salts to mash water)
Salt additions:
6g Gypsum
4g Calcium Chloride
3g Epsom
2.1 ml Lactic acid
Target pH 5.3. (Actual on this brew was 5.32)
My target is always on the lower end for IPAs. Yes it does drop my effeciency a bit but I find that it intensifies my hops and thats my end goal. Keep in mind I am using 100% RO Water. I had thiese same questions when I started adding salts. Honestly he best advice I can give you is brew your recipe, keep excellent notes, make your salt additions and make adjustments on your next few batches until you get what you're looking for. It ahould inly take a few batxhes if that... Good luck, hope this helped