I've finished knitting the 17-inches below the arm hole and tried to figure out how to modify the pattern the way Kate Gilbert wrote it.
I could try to figure it out, but just casting on and knitting the sleeves separately will work out. I'm working from three different balls at once, but since I'm used to keeping track of the cables by knitting it flat, I just switch from ball to ball in each panel area.
Here's a photo of the cardigan so far
And a close up of the cables - see how nice the Comfort keeps its stitch definition? I love the seed stitch border on either side.