If it's any help (I notice on a couple of yours you can see the hard edge of the feather quill even underneath the wrapping and that can catch the back of your hand or just generally reduce aerodynamics a touch (not important on hunting/re-enactment arrows but more so on distance/flight shooting with warbows if you made them for the bigger bows!)) I use a hot piece of steel like a knife held in a flame for a few minutes to burn the feather quill down into the arrow shaft at a taper. It seems to work a bit better than just cutting them at an angle and gives a really neat, flush finish. Once the binding is put on, you can't see the end of the quill at all.
I think for my next set I'm going to copy yours - I really love the look of the natural barred turkey against the two white feathers.