it’s definitely a lift to take seriously. the most important thing is to MAKE SURE you get your arms on top of the stone for the loading part. And if anything feels a little off on a particular day, or you feel undue strain, don’t push through it, be smart about it.
as to training frequency… as long as you feel fine, training frequency shouldn’t be an issue. I actually know a couple guys who used to train stones 4 times a week. crazy. once a week isn’t bad. I think what’s more important is the context in which you train it. I think if you train stones right after you’ve done heavy rows, or pull ups, or anything that strains the biceps, you’re probably more at risk than if your biceps are fresh.