The reason I go for leaders of around twelve feet is that when using an 11ft rod I seldom have to retrieve the line leader connection into the rod rings when landing a fish. I find that when wading I simply extend my rod arm directly above my head and the fish will come to hand. This saves the bother of having to get the join back through the tip ring to continue fishing. This may sound like a simple thing but many a night time tangle has been caused by a loop extending from between the last ring and the tip, while the line leader joint is stuck in the tip ring. Everything feels as if it is working for a while but each fore and back of the rod will be making evil twists that, when you discover the mistake and try to rectify it, usually result in a new leader being required.
Many pundits recommend the use of a single fly when starting to fish at night.
This is understandable and will ensure a less troublesome introduction to the joys of night fishing. The tail fly will always act as a sort of sea anchor on the dropper, regardless of dropper length, causing it to cut quite a straight course through the water, while the point fly is livelier in the current. I have found on several occasions that the seemingly deadly pattern employed on either dropper or point, has suddenly lost its charms when fished in the other position. Widening the casting arc will make it possible to use a dropper with little more likelihood of tangles than in daytime use. A common mistake is to rush the casting at night.