I used to drink about a dozen cups of very strong black full caffeine coffee a day and very little else (well, far too much red wine in the evenings). When I first started I had quite unpleasant caffeine withdrawal headaches for around 5 days but then they disappeared and since I discovered Carte Noire decaf I have not touched caffeine since! I will stick to this decaf, the amount of caffeine I was drinking was so unhealthy and dehydrating.
I found drinking a lot of iced water has got easier and easier as time has gone on, I now have around 3.5l every day to drink which includes my decaff coffee.
I have never got beyond the very first colour on the chart, trace of ketones, and I don't know why but my CDC says its not a problem at all though I would rather see it a healthy rosy pink! I can never test it first thing in the morning because I am up peeing all through the night, every 90mins on average so there is never a "strong" one to test.