Yea, but here it is from "Kelly" as per Roger Rothaaer, who was a trad shooter:
"The 60/120 degree 4 fletch alignment is done during fletching with the three fletch jig. Install two-hen feather and two cock feathers. The following instructions are for right-handed shooters. If you are left-handed, you will do the opposite for the hen feather position, only. First, put on the cock feather. Then rotate the nock indicator of your jig to the left (counter-clockwise) and install a hen feather. This is where if, you are left-handed, you will need to rotate the nock indicator of your jig right (clockwise). Now remove shaft from jig, rotate 180 degrees and return to jig. Put on another feather. Finally, turn the nock indicator back to the cock feather position and install another feather. Wholla!"
Lets remember we now have (Blitzenburger) jig which will set up for 75x105 four fletch as well as doing the method above also.