I had no idea that we were killing a bunch of fake ducks to use!
And are longer (slightly) marks really harder when there's a shot from that spot to attract a dog's attention, as opposed to the dog having to swing with the gun (real, not plywood) and look for the actual bird, with no noise from the field like in a real world hunting situation?
Why three series for a hunt test? A good, hunting, judge who understands bird placement and the variables that go into a day's hunt should certainly be able to get the answers they need in two well planned and active series in a hunt test situation. Does three series make it harder or just longer? Wouldn't four be even better? It's a hunt test, not a field trial.
Again, to each their own. Too many variables in judges, part of the country, etc. to say one is better/easier/harder. It makes more sense to say XYZ is one's "favorite" venue.