The original picture has more of a button style lock which I think might work a bit better for this type of application (these are usually done with shock-cord). I wonder if the cord lord might be harder to use (the pack I have which uses this hardware uses it on the cord that cinches the top closure I believe).

I think I have a couple packs at home that have this type of shock-cord system and I can check what they use later on.
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Victory awaits him who has everything in order — luck, people call it. Defeat is certain for him who has neglected to take the necessary precautions in time; this is called bad luck. Roald Amundsen