Re: how hot ?
I forgot to mention, be generous when you apply the alcohol. You may get you're stock wet but its fine. In the Texas heat it will not take long for it to evaporate. I guarantee you, it will cut you're wait times down by 75%. Of course this will take longer with bull barrels, than sporter weights, but it does work, and work well.
I am in Austin, and shoot in about the same conditions as you. I go through a bottle every 2 range sessions or so. For 99 cents a bottle it's a small price to pay.