We're working on addressing the relay to proxy to by pubkey instead of wss:/.... so you can encrypt your requests once the tunnel is established, meaning the proxy server will not know what you're sending. 

If you use this to pass a Nostr Onion, nobody will know that you sent out an onion AT ALL (i think, i might be wrong though, let's keep exploring...)

nostr:note1afn8643hefhuuhrws7ygfsqy4y7quz6x4t3k8wt9yc0f38rq000qnrmthw