I've fished Benett many times; I've had success with all kinds of patterns, but I wouldn't go without a handful of brown / copper zebra midges. A fun way to fish them is to drop them off an unweighted scud (normally olive green or gray) and flip them towards the dam in Zone 2 (while facing it).
Also, don't forget your dries such as cracklebacks or griffiths gnats or (especially) white cream midges. I like to fish them in the afternoon while standing on the dam. I usually fish them on the South side of the dam in that little corner between the dam and the large retaining wall. There is alwasy a hatch going on there, and in the afternoon, there usually aren't too many people there, especially in October.

Good luck and have tons of fun,
Hydlide