that's great brewing water you have there since for most of the styles you just have to add salts to get the right water profile for that style. If you really want to work on consistent mash pH you should get yourself some means of measuring pH, aim for a certain range (5.3 - 5.5) and keep track of the actual pH you got. On the Wiki I wrote some information on what is out there for measuring pH (http://www.homebrewtalk.com/wiki/index.php/Understanding_Mash_pH#Measuring_Mash_pH
Regarding the brewing water of the different cities, you should not see this to binding. It works for some styles, but won't work for other styles since nobody is telling you what water teatment is necessary before that water can be used in a brewery in this region.
Dortmunder water for example is very alkaline, but a Dortmunder is a light beer. No way that they can brew such a beer with the given water w/o water teatment to lower its alkalinity. And that's correct. Dortmunder brewers have been one of the pioneers when it comes to water treatment for brewing.
The same with Munich water and brewing a Munich Helles.
I'm in a similar boot as you are. I have RO water and need to build my own water and are somewhat scared about overdoing it with the salt additions. First of all the RA needs to be adjusted so you hit the mash pH. Then you want to make sure you have enough Ca. This is necessary for good yeast health and fermentation. Palmer suggestes at least 50 ppm. Some Mg is also good. I keep the Sulphates low for malt based beers and may raise them when I want to enhance the hops a little. The rest you will find out over time when you read more on the subject and brewed more beers. Palmers book has a nice table about the recommended ranges for the ions in brewing water.