I've used commercial VPN with acceptable (think ~100Mbps) but not amazing throughput. But for BT I just set up a secondary on-demand network interface on my Li

I've used commercial VPN with acceptable (think ~100Mbps) but not amazing throughput. But for BT I just set up a secondary on-demand network interface on my Linux server specifically for OpenVPN (just need a shell script to add a couple ip(8) rules, and stick that shell script into the up command of ovpn config). Then I bind my transmission-daemon to that specific interface (bind-address-ipv4 option). This way all BT traffic goes through OpenVPN, but other traffic is not affected. Works for any OpenVPN provider.