I'm afraid I'll have to agree.
This thing obviously survived after being cut open on day 30 something, survived being dumped out, put back in, and is still thriving how many days later? This guy is experienced and if what he says is true about not loosing any babies from his practices, how can anyone say what he does is wrong? What's the basis? Sure it's just impatience, but if that's what he does, that's what he does. If he kills babies, what does that matter to any of us?
Regardless, this is a matter of what you feel comfortable with, not what you think other people should do. I would never cut on day 30 something because I'm not comfortable with it, not because it will kill the baby (I know there are many other big breeders that cut around day 35), but because I don't know how to keep them alive and well for that many days. It's impatient to cut the eggs at day 53 or after the first one pips, but no one says anything about that. It's a matter of what people are comfortable with. Simple as that.
Anyway, I'm off my soapbox. Congrats OP and just remember everyone on here thinks their way is the best and ONLY way. I think you already know that though.