I have a Great Pyrenees, and although I don't live anywhere near Texas, I thought I'd put in my two cents.
Come spring and summer time I use my Furminator every few days, just a quick once over. I don't usually spend more then 20-30 minutes on it, and she is happy to be outside for walks, trips to the park, etc. On REALLY hot days like when it gets to the high 30s or low 40s (Celcius), I keep her inside and she hangs out by the AC registers. I've tried getting her a kiddy pool to hang out in, but she eats them, so that's a no go for us, but it might work well for you.
BTW, welcome to BPO! We'd love to see pictures of your crew!