Rob, I have a bitz jig and can do 3 or 4 fletch, left or right wing by only changing the setting on the jig and using appropriate clamp. Like Chris said.
Bjorn, from bitz's website: "Feather spacing of 3 fletch 120", 4 fletch 75" x 105", and 4 fletch 90 degrees can be selected by a slight screw adjustment. Optional nock receivers available to achieve 60" x 120" 4 fletch or 120 degrees 3 fletch cock vane down or up." Mine is only about 15 years old but you don't need the insert for 4x90, just adjust the setscrew accordingly.