But they are tough, and can be bent outwards, and this can cure the problem. There is no doubt the optional disc brakes will far out perform the drums. I find they have about twice the stopping power. We have had some difficulty finding brake levers with locking buttons which pull more cable. However thanks to Pacific Cycles we have at last got our hands on some.
Higher speeds get more help from the air, lower ones give more time to dissipate heat.
So, either creep down, or have fun and just use the brakes where you really need them, if the risk of finding none is acceptable. Other means af braking may work well if rehearsed. You can also cool brakes with a water bottle squirt anytime. Logging trucks used to come straight down hills with water cooled brakes producing a cloud of steam on a routine basis.