I would highly recomend exercising the warrenty, before going further. All the metal that came off that bearing is inside that engine somewhere. Not to mention clearances may not have been right when final assembled. An
oil passage may have been blocked, which would garantee a repeat. The more you mess with it the more you own it and the less the builder will own up to.
The bearing itself was not the cause of this failure. Replacing the bearing does not fix the root cause. No way the 20 -50
oil was the cause. Short of very high rpm, normal operation in 500 miles could not have caused this. The only thing left is something was not right before it was ever started. That something is still not right.