I'm pretty committed to 20 days, I doubt I'll break before then unless my body sends me clear signals it's unhealthy for me to continue. Friend finished his 40-day water-only fast, same height as me and started 10 pounds lighter, he came out just fine. Not safe to judge based on his experience, I know, but I don't expect there to be any problem.
Also, how much water should I be drinking (in cups)? I think I'm drinking something like 15 cups (about 4L of water). Does that sound sufficient?
Lastly, what should I expect in terms of bowel movements on a water fast? Do the intestines shut down? Constipation or diarrhea?