Hi Jeff,
Full disclaimer; I'm Australian; I do a certain amount of physical work outside, and it is not unusual to get above 40 degrees C for a week at a time. Humidity up in Queensland (tropical cyclone season) can also get pretty damn intense. Sweat, sunburn are par for the course.
I am curious as to your thoughts on how to address water needs in this situation. It's pretty normal to look like you are straight out of the pool in the gym, around here. In your experience are there needs for salts, etc?