probably preaching to the choir here, but if it helps just one person…
I’m fond of those “buffs” - neck-tubes? you know the things. in Phew! Cor Blimey! weather I discovered that regular stops at service stations to soak the buff in water and put it back on, dripping wet… good thing. not in 9C riding conditions though. you got this.
The good ole desert cooler! Well reminded.
Last year went through the Duro valley in Portugal. Over 33c. The locals were stopping for drinks and then would take off their jackets and pour a 2 litre bottle of water over themselves. Jackets back on and away they would go.
Hahaha. Well, even more water is better, I guess. Just make sure your heated gilet is not connected to the battery? 
I was reading about using cool showers, not cold, to cool yourself down.
Apparently it backfires if you use cold water as your body naturally stops blood getting near the skin and so you stay hot ‘internally’. Cool water doesn’t have this effect and so your blood continues to be sent all over and can therefore cool down.
The human body is fascinating
It’s an absolute relief when you go by a farm spraying water!
…as long as it is water and not something else.