Annealing Brass

Forming .358 WSSM cases from .25 WSSM cases required me to learn about annealing. This is what I have learned so far:

So what am I going to do to anneal them evenly? Chuck them up in a drill? This leaves me open to more risk of overheating the case head. Maybe I need a lazy susan or some kind of rotating platform I can put a bowl of water on.