I make a lot of arrows and for the last several years the full length festhers have been getting shorter and of less quality. Even the grading system is changing now.
Since I cut and burn all from full length, I try to get as much usable as possible.
I have tried and tested for several years now and for the most part I can get a 4.5" and a 3.5" cut from a full length. About 30% will only yield a 3" piece after the 4.5, but I am able to make all that work on target, field and youth arrows. With a helical fletch on my Bitz wheels, I have no performane problems with a 4.5" fletch. I use primarily a shield shape for the classic look and a little more air surface - but those who want a parabolic or banana cut I do as well.
There are still some who hold out for a 5" fletch and that is OK. That seems to be for the folk who have hevay bows, heavy arrows and big points.
I don't do a lot of die cuts because I like the way a full length will glue down and hold better. Then I can also get the pefect fletch match for the whole batch with the Young Burner. Sure it is more fuss, more smoke and more stink - but after 45 years I guess you get used to it !!