I love four fletch, I don't use 4 inch when I use them. I use four fives, or four 5 1/2. I often reduce the amount of helical, sometimes straight, when I use four.
For hunting they are quick to load on the string, and give great stable flight, the downside is that at longer distances, such as 30 plus yards, they really drop.
When I use three fletch, I use three 5 3/4 inch feathers. I just like the Classic look of large feathers, don't need them, just love them. I guess that is why I hate cap/wraps, they are too short. Everyone knows that Classic Arrows were always capped at least 9 to 11 inches.
I guess I am just a T-Rex, getting a little long in the tooth.