Help - felting i-cord

I have knit a small bag with Noro Kureyon and I am knitting an I-Cord to attach to make it a messenger bag–so I need for it to be a minimum of 46 inches when done, preferably closer to 48-50 inches. I have felted with other yarns before, but never Noro, so my question is: how long should my Noro I-cord be before I put it in the washer? Thanks for any advice!

I knit an 5 stitch i-cord handle with Noro Kureyon and felted it. Here are the measurements.

Before felting: I-Cord 77” long x 5/8” wide
After felting: I-Cord 53” long x 3/8” wide