I got a 2nd washer bottle setup and a couple cool OEM Toyota switches on ebay for $15. I got a universal setup for $15 as I didn't want to invest too much into it. The only delay is finding time to make a little mounting bracket.
Evaporative cooling (sweating, misting systems, etc) can reduce temps as much as 20 degrees in auto applications (mainly turbo intercooler application where a trick is to redirect washer bottle spray and cool things down). This idea came to me from a discussion w/ Joyce (someone that races a turbo 3rd gen 4Runner). She mentioned a trick she uses in racing is to redirect the washer bottle spray for some trick intercooler spray.
I found that in 3rd world areas, it is common for them to spray the radiator w/ water for the evap effect. when they start overheating.
The wet cloth in front of the radiator is the same effect, cooling the air before it hits the rad. In AUS, they will set a porus bag filled w/ drinking water on the front bumper; after driving all day, they have ice cold water just from the evaporative effect.
The way it works is the energy it takes to convert water to steam is heat. So, you "suck" the heat out of the metal by hitting it w/ water vapor. Same goes for your skin when you sweat.
The way I understand it, the finer the mist, the more rapid/effective the cooling. I am not sure, in the case of the radiator, if a fine spray from a washer nozzle is enough but will try this and add some simple mist nozzles later.
I don't have overheating problems. My idea is that it will reduce temps by basically giving me a "bigger radiator" during the times I hit the spray. So for those long grades w/ the AC on...or some higher stress event, just hit it w/ the spray.
It's a "free" temporary cooling booster so I think it's a worthy experiment, esp. since I live in the ideal climate for it to work best.
I will update w/ photos this weekend hopefully