I am more than 10 cms into the seleves, both at the same time, but not both the same but mirror images. I did the ribbing before the cable pattern starts with smaller needles. There is a little error in the first chart, on row 13, where it sais to purl two stitches that are part of the knit cable after crossing, but it is evident from what you have knit before and obvious that it is a typo.
Thanks for passing by!