With ABC, you can set your ratio so it automatically stops at a certain point. For instance, you can set it at 100%, which means you will upload exactly the same amount as you downloaded. When it hits 100%, ABC stops seeding and will move on to the next torrent in your queue.
You can change your ratio to 125, 150, 200, etc. I think you change this under the Global Upload Settings, or something like that.
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