RE: Feathers?
With feathers I use 4" over 3" anymore. The weight gain is next to nothing, and the 4" gives awesome arrow stability.
Spray them with some waterproofing,and you'll never have a problem with rain. I play with all sorts of fletching during offseason, and I'm sure I will again this year.
Next season will find me with feather fletched arrows in my quiver again I am sure.
Dan