Joe, if I purchased a round base router and found the base to be eccentric to the cutter, it would be returned for refund in a flash. The beauty of a round base is that you can rotate it as you go along, especially around corners. The only photo-shoot I recall where a machine was running was the "multi-purpose cube", where I was able to stand back from the lathe to take the shot. You know me Joe, if there was the slightest excuse for using a template guide I would use one, however for trimming a straight edge a template of sorts would be required, also for a bearing cutter, not only would a straight edge be required, but also a means to steady the router. In my usual humble opinion, both of these methods would turn a simple two minute job into something else.
Nothing but heaven itself is better than a friend who is really a friend. - Plautus