Cheapshot, I compress the nodes as I'm straightening the shafts. I start with the internodes first, let them cool for a day and straighten the nodes and let them cool for a day then re-heat and compress the nodes and heat temper the entire shaft. Oil is not necessary but I sometimes use it when straightening but not when tempering. When you heat up the cane you will notice droplets of "sweat" appearing on the cane. When you see it, its ready to work.
I have never tried to heat straighten green canes. I do, sometimes straighten green canes a bit without heat as they are drying. Pat