I prefer popping baby balls and probing older snakes once they reach the 400g range. It's just so much easier to pop them as it only takes a second to do. You really don't apply much pressure at all and I wouldn't really call it squeezing them but more like rolling your thumb.
I have never been shown how to do either. I tried popping before but I think I just ticked her off because I had no idea what I was doing. I got one snake from a friend and she said it was a boy so I call the other one a girl. LOL