I shot ZZ's at Sandanona a couple years ago and the best shooter there used a tightly choked, 32", high rib, monte carlo-ed trap O/U. The shooter was Charlie Schneible of British Sporting, and I know it was the shooter not the gun.

But I think the choice was interesting; he could've used any type of gun he wanted (he's a shotgun shop owner and excellent shooter) and he chose a serious trap gun.