For my 40# OTF
recurve I have Bohning X-shield fletching on my
ACC’s which are 1.5”
The sole reason I shoot that size of fletching is because I bought a new set of fully made up arrows arrows that someone else had ordered but then never collected so they were heavily discounted. They perform very ŵell out to 100yds and any misses are solely operator error.
I think people go for big fletching indoors is more to stabilise the arrow as quickly as possible over the short distance - I’ve seen recurves shooting 4” vanes indoors on very thick arrows such as 2516’s.
Karl