I live in TX also and I use a dough that is high in butter. I refrigerate my dough and take it out of the refrigerator about 45 minutes before i want to use it. I like to use it while is still cool but no cold. After I cutout my cookies and they are on the cookie sheet I pop the whole thing in the refrigerator for a good 15 to 20 minutes until they are well chilled. They go in to the oven straight from the refrigerator. They hold their shape beautifully. I use fondant and royal for my cookies. The fondant can get soft and sticky with this heat and humidity but I usually just knead in more powdered sugar and I do not have a problem with the royal icing. I bought an inexpensive stand fan that I use help dry the cookies. And last but not least I try to work in the late evening when it is a little cooler. Hope all this helps. Check out my cookies, I just did the square florals this week with days that hit 90 degrees.