My PSKs are Altoids tins and I only wrap them with about 6 or 7 (I'd have to go count...maybe it's a few more) wraps of paracord. To start I make a slip-knot and a large loop that is the initial wrap. The last wrap is pushed and pulled under a couple of other wraps and to undo it, I just need to get the end free a little and pull. I probably should, but I don;t worry much about waterproofing mine.