I have the Chasm. Here is what I've done so far with 1/8" shock cord & a cord lock from Amazon. I like it but it's a little... floppy, I guess is the word. When I saw that North Face pack, I realized this is the way to do it. I think it looks neater. I found these on Amazon but it looks like I bought the last one!

Edit: I'll be using the clips without the attached cords that come with them.