The feathered border is finished, now here's a bit of a tutorial on how I did the feathers. This method will work for borders from around 8in wide, up to 12in. I used it previously on two borders combined.
Backtrack to the teardrop and quilt feathers around the outside of the second circle and into the third circle. Combined with the teardrop, this forms part B of the repeating pattern.
When you get to a corner, be sure to place the corner 3/4 circle centrally in the corner.
You may find that the circle doesn't fit neatly into the length of the border. The simplest way to check is to measure across the circle (its diameter). Add 1/8in to this to allow for a gap when you trace. Then mark this interval all along the very edge of the border. If you get to the end and it perfectly meets the centred corner circle, then all's well. If there's a gap or overlap, the easiest thing is to squash or stretch each circle (or just a few if needed) a little bit as you trace. My bowl was 5in across, so I marked out 5 1/8in increments along the edge of the quilt, right at the very edge of the fabric. In a few places I stretched my 'circle' out by as much as 1/4in, and it's not noticeable. Another option is to allow a gap between the circles at the corners and to draw in a smooth connecting line. Does that make any sense at all?