There is a much wider range of casting techniques available to the Angler who fishes mainly with the Single Handed fly rod than their is to the angler who predominantly uses the Double Hander. This is not because you cannot perform the same casts with a Double Hander as you can with a Single, but simply because in the majority of cases, the species you are targeting with the Double Handed rod (usually Salmon) have a different agenda as to why they take your offering in the first place. Therefore, when fishing with a double hander for Salmon, it is not necessary to learn such techniques as double hauling, or the many slack line casts that you will require with the single handed rods when targeting feeding fish such as trout and grayling for example.
However, you may want to incorporate some of the most common casts that we use with the Salmon fly rods, (the very efficient Spey Casting techniques) into your range of casts with the Single Hander when fishing for Brown Trout, Grayling or even Sea Trout throughout the night. The mechanics are exactly the same as with the double handed rods, the only difference is that you are using one hand as apposed to two, it is an easy technique to learn, is much safer, (especially in windy conditions) and will allow you to reach places not usually accessible to you with an overhead cast especially where there are obstacles behind such as tree lined river banks where an overhead cast is impossible.