Perhaps I can ask you to engage in some logical thinking?
If our performance is seriously degraded as our core temperature rises, what would be the best way to dress for performance?
Staying cooler is better.
Wearing sweats, caps, sweathshirts, etc, is counter-productive and a hindrance to your efforts, unless water loss is your goal.
Diuretics, as simple as coffee, are more effective, and don't impair your performance as much.
Cooler core temperatures will allow the human machine to perform optimally.
Water weight, as you call it, isn't always a bad thing. As long as your blood pressure isn't funky, a little water can help with your resistance training.
Remember, let common sense prevail.