Obviously we will all have differing opinions regarding your characterizations and categorizations, primarily those within the group you call "Informed Opinion."
The title of the group itself begs the question: "Informed by whom?"
Some of these may simply regurgitated the thought that came from one of the other groups you have listed further up the food chain, whereas others do attempt to use their experience and well developed thought process to provide truly individualized opinion. Simply exposing one's opinion for either validation or ridicule does not necessarily add any credibility to that opinion; otherwise, we'd all be geniuses.
Stating my opinion of who truly put forth unique effort would serve no positive purpose, neither would naming those I believe do not belong on the list; but I would add to your list the names of Jim Booth, Tony Peters, Jon Bible, and, believe it or not, Scott Taylor and Peter Osborne.
That said; remember that the Internet still represents a tiny fraction of amateur umpires. There are many others who, for one reason or another, have chosen not to jump down to our level.
But on to your premise.
Due to the lack of a single MLB "approved" authority; we have no choice but to consider the alternatives. We could, I suppose, pick one and follow his/its thought blindly forward. Some of us do. I've heard over and over that "If you accept the PBUC on this, then you must accept it on that." You may substitute, Evans, Roder (WUA) or Childress for PBUC in that statement.
In my opinion, that would be foolish. While it is messy and at times ugly, I suggest that the cafeteria approach, adding one's experience and a logical thought process (some refer to it as "common sense") to the mix, works better.
There are times when Evans makes far more sense and is in tune with the tradition of the game than Roder. There are times when Roder makes his case better than PBUC. There are times when one's own experience, understanding of how the game is played and logical thought process will assist him well.
How do we select, on any given subject where they may differ, one from the other? That's where one's experience, thought process and understanding of the game become even more important.
Any Internet umpire can quote verbatim Evans, Roder, Childress, or for that matter, Booth, Bible or Willson. (And several do) I look to those who do not start with quotes from the so-called authorities, but rather start from the point of the intention of a rule, the history of the rule, the application of the rule and the most obvious consequence of the application of the rule. Then I look for support of their thought process more so than support of their end result.
When everything lines up nice and tidy, it's easy. When it doesn't, well, again, that where experience, an understanding of how the game is played and a logical thought process comes in.
To steal a thought from an acquaintance: If, through this messy process, I can be consistent and confident that my ruling is right in any given game situation to the point that I can bring the others along with me, I have the right answer.
[Edited by GarthB on Mar 3rd, 2003 at 11:43 PM]