Thank you for the kind words. I am not really sure how this is broken down, but for me a short term dry fast might be 12 or 24 or 36 or 48 hours. Even 3 days like Esther's fast (Esther 4:1-4 and specifically 4:15-16) begins to be fairly long and i would say very difficult for most people.
If you are interested in exploring a dry fast for yourself, i would encourage you to resist minor thirst and drink as soon as thirst becomes moderate and persisting (where it begins to become difficult to think about anything else besides how amazing it would feel to drink a glass of water!). Resisting a thirst that reaches beyond this level might become a bit risky. I'll be perfectly forthcoming and say that once when i was less experienced in dry fasting (and bodily less capable), i resisted med-heavy thirst (and becomming heavy in the final 8 hours or so) one time for the final 24 or 36 hours of a 3.5 day fast and ended up with substantially dry, peeling skin as well as nausea that lasted for about 10 days (which was nursed along through additional water-only fasting). By contrast, i went 5 days (or about that) in each of the past 3 months with no such ill effects but nor did my thirst ever reach such a strong level.
After pushing myself too far that one time, i determined to be considerably more cautious thereafter. Initially that i would drink immediately upon moderate and persisting thirst... and eventually i decided that i would allow my thirst to persist for a while in moderation, but once it began to exceed that level I would drink right away. With this policy i have not encountered any problems since and have only felt good.
I would be delighted to talk with you about spiritual fasting and i think a pm would be the perfect place :,).