Just my two cents worth, as someone who has been on UT since June of 08. I just took two weeks off, but nonetheless, I think I have some experience to share. I have only taken in as much as you are mentioning during an attempt to do the urine fast, which I was not successful with. Nothing wrong with the fast, just that I didn't choose to stick with it. Anyway, I have had dramatic results with UT and have only been ingesting it in the morning, and always no more than 1/2 cup, but mostly for the past couple of months, probably about 1/4 cup.
I went off of it to test results, which I will report on separately, for herpes, but even though I feel that problem is now resolved, I am back on UT because it helps me so much with my sinus condition. It seems that I need to keep with it to have an effect on my allergies as far as environmental effects on my sinuses go.
As for food allergies , I feel that there has been a huge effect, but I will say that trying to use UT while still ingesting the offending foods was futile. Going off the foods and staying off for awhile has allowed me to reintroduce them with little to no ill effects. I tested very allergic to wheat, dairy, soy. I rarely go out of my way to eat soy, dairy has been mostly eliminated from my diet because I can see that it does still cause reactions. Wheat was eliminated for quite some time and after cautiously reintroducing it, I am doing better with it. I can live without it if need be, but now it doesn't make my joints swell up anymore.
In the past, I tried eliminating food groups and then later reintroducing them. The immediate reaction would be very negative. Using UT along with eliminating the allergens has been a much different experience. I am not totally unallergic, but can tolerate much better when I have ingested certain foods.
I know that your concern was about dehydration and I have rambled on about food allergies . Sorry. I just think that you could try cutting back on the UT amount and will still get good results. Might be worth a try.