I modified a Bitzenburger jig by cutting off the cradle, making a spacer out of some scrap aluminum I had, and re-attaching the cradle to my spacer, allowing up to seven inch fletching, not that I ever used them that long, but I could if I wanted. I used a standard clamp, aligning and pinning the tip of the fletch with those pins that have a little knob on them. Sure sped up the process for making English long bow arrows, and believe me, back in the day, I ran through a lot of them. If I saw a shot that looked interesting to me, for whatever reason, I took it, the fate of the arrow be damned, HaH! I'd take a picture of that jig but everything is scattered around in four storage areas and I can't put my hands on it.
Robby