Regarding presentation. Presentation is about 75% of effective fishing. However, at any given time, one's presentation is a given. It is what it is, for the present. It can improve, but at any given time it is what it is. Then, other factors take over: the pattern the fish are feeding on, etc.

Given that the gentleman said he was fishing and not catching, and, with a different pattern that was working, became successful, leads me to think the fly pattern may have made the difference that particular time and location. No guarantee about future performance though.