Have you thought about getting one of those misting systems?
I have seen them, but I'm not interested. around here they have misting systems on almost every outdoor patio at restaurants and we have even tried the home ones that connect to the home water supply and I have seen that to work properly to where they cool without getting you wet they need a high pressure pump with super fine emitters, home systems without the pump just can't produce a fine enough mist to evaporate and cool the air without getting everything wet - - considering this I suspect that the systems they sell for the slingshot would not work to my satisfaction I dont want to get wet when I'm riding or to have the slingshot sprayed leaving spots everywhere