I do a lot of descending and I'm over 200 pounds. I have had those 'peel and stick' patches come off due to heat, but have not experienced a tire failure from heat.
My current bike has Mavic caliper brakes with Dura Ace pads and they seem to work better than most others I have tried. I like to switch between the front and rear brakes when I can and give them a chance to cool. Rim brakes can fade, even the canti-lever kind.