I have tried splicing in the past. And it did turn out pretty good.
Splicing gives you a whole new way to be creative with your arrow building.
I think one of the details you need to pay attention to is the thickness and width of the quills on the various feathers you are using.
I found it a good first step is to sort thru the un-cut feathers and rough group them by quill thickness.
I did not like the looks of my results when I just tried to use the pieces as they fell - and ended up with a thick piece of quill butting up to a thin piece of quill.
I used full length feathers, and spliced only about a 1 1/4" solid white or yellow on the back of barred.
I put the 2 pieces in my fletching clamp, and put a small drop of Fletch-tite on the ends of the quills, and pushed them together and let them dry. When dry, I would stroke them to "marry" the feather barbs together.
Then would chop them to size and shape. Another tip - put a pencil mark on your chopper at the point you want the splice to be after chopped. Then line up this mark with the splice. Makes it easier to get all the feathers chopped the same.
Hope some of these ideas help you out.
Chinook