Re: An easier to use donkey ear
Jack Dover
What you say is correct.
Bill's type of the miter shooting board comes in pairs really, or sometimes have both working ends. The reason why they should come in left- and right- variety is exactly what you said: we need to reference the same edge or a face to a fence, preferably in the same location. There's a pretty good explanation video from Bob Rozaieski: https://www.youtube.com/watch?v=C5BgSiar3Ws
Bill seems to prefer ensuring that a fence and every piece are 100% straight, parallel and even - perks of being a hybrid woodworker with a good machine setup. Another way is to make individual shooing boards or position a fence such that it could be used from both sides. Others might prefer the second option if their methods don't produce parts accurate enough. I mean, error is accumulating, e.g. when mitering a crown molding pieces that were milled a few days ago most probably aren't perfect the way they were, a case might have some variance, etc. And I think that if a miter line shows — it's a botched job really, so whatever makes them tight is the right way.