. . . . . One thing any semi-serious dieter will know is that your weight is mostly a reflection of how much water is in you. . . . .
I'm sorry, but your weight above so called "normal" what ever that is, is mainly a reflection of how much FAT is in you, gorgeous, hunky muscle men excepted.
Yes, your weight will change greatly with your degree of hydration, but if I don't drink anything on a summer afternoon, I can sweat out a good five pounds after two or three sets of tennis, and I have measured that because I was curious. I don't consider my self to have lost an ounce when that happens either because after a few glasses of water, I am re-hydrated. The body balances all that out by itself, and that's a good thing too. You "lose weight" when you lose fat, not water. Of course you will "gain weight" if your body absorbs a lot of your water from an enema, but it does the same thing when you drink it, and I don't know anybody who complains that they gained weight after a glass of water, while most of us will complain that we gained weight after that second piece of chocolate cake preceded by an afternoon of chips, four hot dogs, an ear of corn, two burgers and five beers at an all day pig-out BBQ.
I remember when I took our older daughter to the pediatrician and she was weighed when she was about six weeks old. The pediatrician subtracts about an ounce for an infant diaper when they weight them. But on this occasion, the diaper had just been wet and the nurse recorded the weight with the wet diaper, and I informed the pediatrician of that. His response, that I initially didn't like, but then agreed with after a quick reflection, was the couple of ounces of urine was inside her five minutes earlier, and had she been weighted then, she would have had a dry diaper. "Water weight" all balances out in the end, and it is neither a net gain or loss in the long run.
Lost or gained water weight isn't really weight gained or lost. You have to lose fat to do that. I hope we have all agreed that enemas don't cause you to lose weight either. It just lightens the load inside the colon and gives you an enjoyable activity to do instead of eating.
The concept of how your pants fit is a good one, but no one really gains or loses that much weight to make much of a difference in a day. Month to month, it is a very good indicator of how you are doing.