I have lived in Arizona it can get good and hot there. Looking stupid was the lest of problems heat exhaustion and heat stroke can kill you. Armoured mesh is a good way to go but have some thing light underneath the sun will burn you bad if you do not. For some grate meshMotoPort .
The vests you soak in water use Co-polymer polyacrylamide crystals they hold something like 80% its volume in water (used in holding water for plants some times and can found in some plant shops). There are many people that make vests and other items with the crystals get a good quality item they last a long time and can be used over and over.
Other tricks are personal misters there ok but a little hard to work. Misters and Mist Systems by Misty Mate. Put a hydration pack on the back under a net when you stop (stop a lot) dump some of the water on you, the water will be hotter than you may like to drink but wont shock your body like using cold water will. Drink lots of water a gallon or more a day stay off the coffee, tea, pop and alcohol. Find shade to rest in, rest often, ride hard in the early morning its coolest then (watch out for animals they move around most then to).

In the high humidity riding faster for short burst dont over do it or you will fatigue. Use coolmax COOLMAX® - Only by INVISTA or something like it the idea is to dry wet skin this drying will cool you down (harder the high the humidity). Eat spicy sweet food (more of a feeling cooler than cooling you down any).