I see. Every spreadsheet has it's own "range" of ions. I guess what we're seeking now is what will make a beer representative of the water source, but not taste like crap?
There are several criteria by which one can jusdge the "goodness" of beer. Some of them are
1. Tastes good to the brewer
2. Tastes good to the brewers wife
3. Tastes good to the brewers friends
4. Wins ribbons in competitions
5. Is authentic i.e. is a good "clone" of some existing or past commercial beer.
6. Is stable i.e. doesn't change much over long storage time.
Each of these (and there are probably more) produces a slightly different beer. You seem focused on authenticity which is fine if that's really what you want but you should keep in mind that you can brew a better Burton ale than the original Burton brewers did because you have more knowledge and better technology on your side. If those people had known how to remove sulfate from their water they probably would have done so. But the fact that you are brewing a Burton ale says that you want some Buton character because if you didn't you would be brewing something else. So the idea is to get a better tasting beer with some Burton character and, IMO, the only way to do that is to start with low mineral water, adding some gypsum and calcium chloride and then doing it over and over again until you find the mix that suits you under any of the above criteria. In the course of your explorations you will find which you like best, which your wife likes best and which is most likely to win competitions. You will then be able to tailor your brewing (e.g. less sulfate to please Mrs, more to satisfy the style Nazi's) to your target "market".
Obviously, researching the beer you intend to brew is a good place to start. Continuing the Burton example research will show you that Burton water is modestly carbonaceous and highly gypseous with a low RA so it should be clear that you would need some sulfate to attain Burton character. If researching Pilsen you would find the water extremely soft so it is clear that you would brew Pisner with soft water if you can. Etc.
I see Palmer's ranges, but where do those come from?
That you would have to ask John. There are hundreds of 'published' water reports for various famous brewing cities floating around on the internet, in textbooks, in magazine articles, in the AHA style series monographs etc. I expect he poured over those and took the extremes but I really don't know.
Where can I find acceptable ranges for all styles?
You'd really have to do the research your self. But the research should only give you a general idea. You will really need to experiment to hit the sweet spot for any particular style. Accordingly I recommend concentrating on one style i.e. brewing it more often than any other. When you have mastered that one (note: it took me 20 yrs to get Pils right) you can move on to another. But the things you learn trying to brew a good Pils will help you make a better stout too.
Where can I find a document that shows high RA is good for dark beers, and low RA is good for lagers/pilsners?
You can't because it isn't really true. RA was developed for comparison of brewing waters. If a water source has high RA that doesn't mean it can't be used for brewing lagers. It just means that the treatment of the water and grain bill need to recognize that the source water has high RA. Conversely, you don't need high RA to brew a good stout. You just need to know what to do to low RA water in order to produce good stout from it.
I'm not after replicating Munich's water or anything like that, but seeking to get the local water to produce a decent beer.
The recommendations in the Primer will get you a decent beer. From there you can step off towards better beer.
Once I learn the acceptable "ranges" of ion concentration, and we start the mash and use our pH meter, how do we know how much salts or acid to add to lower or raise pH?
Salts have limited power to lower pH. It takes 3.5 mEq of calcium to "neutralize" 1 mEq of alkalinity. So the best bet, IMO, is to set calcium to 50 mg/L (lower for some beers) and then rely on acid to get you to the right pH. The best way to figure the amount is to withdraw about a half pound of the grist, mix it with the water you intend to use, warm it to about 140 F, let it sit for a minute or 2, draw off some liquid, cool it back to room temperature and measure the pH. That's the pH (or close to the pH) you will get in the main mash. If you want a pH lower than that then add 1% sauermalz to the grist for each 0.1 unit pH drop sought. This should get you pretty close. Adjust on subsequent brews. Or, if you prefer another acid, add it incrementally to the test mash until you get the desired pH and scale for the full brew. The test mash can be the whole mash but the danger of doing this will the whole mash is overshoot (i.e. you add too much acid and wind up with pH 4.8). You can try to correct that but can windup with the acid bottle in one hand and the alkali jar in the other chasing the elusive pH.
Following the recommendations in the Primer should get you reasonably close.
How much is too much gypsum?
It's the amount that makes the beer too "hops forward" according to your chosen criterion of goodness.
How would we know to add chalk instead of gypsum?
They have, in terms of pH control, opposite effects. One adds calcium to lower pH (though it is generally better to use acid for this) and chalk to raise it however chalk should only be added to the mash if a pH meter measurement indicates a low mash pH. It should only be added to the water when the ultimate in authenticity is sought including an authentic brewing experience i.e. you are going to do all the things a, for example, Munich Helles brewer did to Isar water to brew a Helles which includes decarbonating it so you prepare cabonaceous water and then procede to decarbonate it. Seems a waste of time to me.
How much is too much lactic acid?
An amount that a) lowers the mash pH too much or b) results in an undesired lactic quality in the finished beer.
I have read the primer, and it makes sense, but then a million more questions pop out as seen above.
That's to be expected. The Primer represents an extreme simplification of a complex subject. First, the chemistry is intricate and second there is the variability of styles and water treatment practices which have evolved over many years of brewing.
At this rate I don't know that we'll ever figure it out!
I've been at it for over 20 years and there are still plenty of questions in my mind too so don't expect quick gratification here. It can be an interesting area of study though.