It's debatable as to if the high-heat method (above 1333F) is necessary. If temps are kept just below the 1333F critical temp, (like CSC) colors can be restored yet hardness maintained. It becomes a recoloring process rather than a rehardening one. It greatly reduces the chances of deformation. It requires a digital controller that slows the initial heating of the oven, to prevent exceeding the critical temp when heating up.

Regards
Ken

I prefer wood to plastic, leather to nylon, waxed cotton to Gore-Tex, and split bamboo to graphite.