jimjimmysticks : I selected as similar white and blue feathers as possible, i.e. in which the barbs are in same angle and roughly at same position in the feathers to ensure they are as similar as possible. Then I cut the quill as straight as possible with sharp blade to avoid cavities between the pieces, the middle ones exactly 2 cm, longer one ca. 8 cm and the tail one ca. 3 cm. Then I used common clear scotch tape to join the pieces together from their outer side and the barbs barbs helped in this by sticking easily together because of their correct angle and thickness. The taped package was inserted to 5" ray-shaped feather cutter and after cutting glued normally on the shafts. Removal of the tape and drops of glue to secure the quill ends finalized the feathers.
Almost forgot... First, before fletching, I dyed the shafts by natural white and then by sky blue spray paints. Dark blue felt tip pen and a battery screw driver was used to make the ring(s) between the colours.