NCDownloader: simultaneous torrent processing limited to 30?

I can’t find a magic number in the ncdownloader code limiting this to 30, and I can’t find a limit option in aria2. For aria2 I have set max-concurrent-downloads to 65 and max-connection-per-server to 16, which as I understand it has nothing to do with a limit on how many different torrents it can process simultaneously.

Is there an option somewhere I’m missing?