I made one last night and as I was making it I understood how to attach the cords.
I have little weaving expierence and it still looks great, I'll post pics soon. I really like this design and now that I have a loom you'll probably see a lot of them.
I made my loom bigger today so I can make larger sling pouches but, as you said, it can really be any size within reason.
To anyone that didn't undestand how the cords were attached: The retention cord strands are woven in a circle around the woven pouch. For each strand you weave through, you'll have 2 strands for the cord because its folded in half, so you'll only need a 1-4 cords woven around the outside.
The release cord is attached be pulling the strands through the eliptical woven release cord strands an then folded over like you would when you normally attach cords to a pouch.
Thanks hubert!