I also have a Hetzner box. 2x3 TB in RAID 0, 1Gbit, 16GB RAM. Running Ubuntu 16.04.2 and latest QB.
I have 0 issues with seeding or getting good speeds. I'm an uploader for one of the larger HD sites and can ALWAYS max my connection on new uploads and get a great ratio. Using either Deluge or Rtorrent. (personal preference for quick ratio is deluge, long term rtorrent).
My QB install seeded at about 85% capacity out of box. I had it further tuned by Liza from Serverbabe.io and am now at what I consider 98%.
How many torrents do you have seeding total in rtorrent? The nature of torrents and peering is LOTS of variables. But I typically only have 10/300+ seeding at a time. I get good speeds when people grab them though. I'm guessing you both fundamentally understand torrenting though, so I won't go into explain all the variables.