I am going to preface this statement by saying I am not a scientist, and don't have a complete understanding of water chemistry. Bru'n Water is awesome, and it is where I got almost all of my water knowledge.
I start with almost Pilsen soft water. I make as few changes as possible to my water.
I add Chalk (I haven't had the problem you have noticed Martin, but I also only use the strips) only to my very dark beers, if my pH is too low; and then it is usually 1/2 tsp or less, confirmed by pH strips.
3-5g of gypsum goes into the kettle if I am doing a very hoppy beer.
3-5g of CaCl goes into the kettle if I am doing a malty beer.
1/2 tsp of 88% Lactic Acid goes into the sparge water. (I think this might be a superstitious thing, but it works for me, haven't done side-by-side though.)
In the future, I am going to move to pickling lime for my pH adjustments, and get a pH meter. Right now though, I make the fewest adjustments to my water as possible. I did one beer where I added 3-4 different salts, and it was an abject failure. My pH ended up wonky, and the beer ended up tasting kind of muddy. Simplicity is your friend.
Also, completely off-topic, but I would add some of that "sparge water" as a mash-out step in order to even out your runoff volumes. It will help some with efficiency.