True but the min is 61 right? What is your 3 year old nephews IPD?
we just put it on the minimum, we didn't use a configuration utility. And really, worst that happens with too high of a convergence is they flex their eye muscles a bit harder than normal for a short period of time. The amount of time anybody will put a 3 year old into VR for is far outweighed by the time they will spend outside of VR. Certainly to the point where people don't need to speak up about questioning parental decisions without any real research to back up their fear.