4 X 5 1/2 inch parabolics with lots of helical for me.
Believe it or not sometimes you don't make a perfect release...or there might be some wind blowing....or you may not be able to stand tall with perfect Olympic target archer form....or your feathers may get damp...or ..or..or....
When any one of those things happens and the biggest animal of your life (insert deer, elk, bear etc) is standing in front of you, trust me, you'll be happy for a little extra feather.
I really wonder how many guys that worry about "loss of velocity at long range" due to big feathers ever shot an arrow at "long range". Frankly, I practice to 50 yards and beyond...sometimes FAR beyond...all the time in our pasture and I can't shoot the difference 3 to 4 fletch, 5 inch to 5 1/2 inch, parabolic to shield cut. I doubt very many can.
Just my 2 cents from 30 years behind a recurve.
Ryan