From the answers to these simple questions you can determine the outfit you'll be using most. Then the assembled outfit should balance in your hand. While holding the grip the rod shouldn't feel butt or tip heavy. This will make for comfortable, controllable fly fishing. We start by choosing the line for the type of fishing we intend to do, then match it with a rod and then a reel.
Longer rods are easier to cast than smaller ones.
The choice of weight forward versus double taper fly lines is a subject of much debate. It simply doesn't matter much in this case. Rods in length 8 to 9 '. Again, longer rods are easier to cast and can cast longer distances, especially with weight forward or rocket taper fly lines. Double taper fly lines are used less in this kind of fishing.