I started using two Fletch a year ago. I have not had any issues. Usually I take the shortest turkey feather out of all the feathers on both wings, and cut it in half. That is the length I use for the rest of the feathers. Usually around 4 to 5 inch long over all, and trim back a 1/2'' of quill on each end for sinew wrapping on a river cane. Then burn in a profile with a stick and fire. The upsides have already been said. More arrows per lot of feathers and no worries with a "cock feather". No matter how you put the arrow on the string, the feathers are on top and the bottom of the arrow and ready to be launched.
Of course I am using stone or glass points, so I just line the two cutting edges with the fletching.