The act of heat straightening tempers the shafts somewhat anyway. After straightening cane or hardwood shoots I run the shaft back over the heat(our gas kitchen stove), starting at one end and spin the shaft as I work down towards the other end then lay it flat to cool.
Be careful when you get to the far end as steam coming out can give you a pretty good burn. You may have to still do a bit of hand straightening but usually without heat and only mild pressure.