I learned that '30/60/0' was the 'default' setting for most chains. In recent years Oregon has recommended 55 degrees.When I first started grinding, I put a brand new chain on the vise.....to me the 55 degree angle matches up to the new chains angles better.....
There might be some differences between cutters on different brands of chain as well.
Some differences might show up in a laboratory setting, but it as noticeable in the field. So unless someone is very specific, just pick something and run with it.