I've 'hugged' a few kettles in my day, to good effects. I usually use a tape measure to figure out where it needs adjustment. Then just give a slow, smooth, gentle squeeze. Patience is key.
It's funny, because my dad would always warn/scare me to be really careful moving the family kettle (so as not to knock it over), because he said once they went out of round, they were no good. So I've passed up kettles in trash heaps because they were out of round (I had the good sense to grab the grates, of course). But now that I'm hanging out with this bunch of lunatics, I'll never leave one by the side of the road again!