Hello fellow Texan! I have my first round of quail that I plan to put outside soon so I cannot speak from experience, however, I do have some plans to try and keep them coolish. I purchased self filling water cups from rent-a-coop which are big enough to put an ice cube in, and then I plan on having a fan run on one part of their cage 24/7. I read on here once that someone had a fan blowing into their cage to keep their quail cool and they liked it. I'll see if mine feel the same way.
I spoke to the breeder I got the eggs from, she used to live in my city and said they should not have a problem so long as they are constantly in the shade. For reference, heat index here during summer is normally between 115°F-120°F, night time temp (no heat index) is normally mid 80's.