I support what you are doing, but I have some questions.
What are you doing to stop your location leaking through torrent trackers? I believe bit-torrent through Tor is not anonymous in and of itself. Is your torrent client doing hostname lookups via the conventional UDP? Have you made sure you are not leaking these requests? There have been many privacy leaks through bittorrent clients in the past, and I was wondering what steps you have taken to mitigate against this possibility.
It's not BT through Tor. Which is good because BT over Tor is a terrible idea :) You sent your file to his server over Tor, and he seeds it via completely normal means until there are 20 other seeds.
Ok. So the "hidden service" is not intended to be anonymous then? Just as a check to ensure that the user knows they are on Tor? Because, in order to be the first seed, you will generally leak your IP. If not, what steps have you taken to make sure the first seeder (the host of this service) are anonymous?
Yes, but that's how Tor would work even if he wasn't using hidden services. The point of a hidden service is to give anonymity to the server as well as the client. But in this case, his server isn't getting anonymity because it is simple to locate.
What is the point in using a Tor hidden service then? If the point is to give anonymity only to the originator of the file, then they can already do that by connecting to your service using Tor, but not via a hidden service... By using a hidden service you're just doubling the number of Tor nodes that have to transfer the file initially from 3 to 6... The point of a hidden service is to provide anonymity for both parties.
What are you doing to stop your location leaking through torrent trackers? I believe bit-torrent through Tor is not anonymous in and of itself. Is your torrent client doing hostname lookups via the conventional UDP? Have you made sure you are not leaking these requests? There have been many privacy leaks through bittorrent clients in the past, and I was wondering what steps you have taken to mitigate against this possibility.