I think water building can be over done. I've found that it's easy to end up with a salty soapy beer by overdoing the additions. I probably over simplify too much, but this is my method. After spring runoff when my well goes back to normal, I use almost no additions. i have trypical NW water. Maybe a dash of gypsum in a hoppy beer or a dash of CaCl in a malty beer.
This time of year I use distilled (no RO readily available). Hoppy beers get 6-8 grams gypsum, malty beers get 6-8 of CaCl. Balanced beers get a combo. Light colored get 1ml of lactic in the mash and sparge. Medium color get 1ml in the sparge. Darks get no acid. Its not scientific, but it works for me without off flavors. The one time it didn't work was in an attempt at a 3.5 abv brown beer, which turned out too acidic and I had to fix it with a touch of soda. I dont know what happened there other than I might have used lactic when I didnt need to.
Anyway, I suggest going easy on additions.