Through three nested VPNs, about 10 Mbps each way, with 100-150 ms rtt. Plus Tor, about 1-3 Mbps each way, with 500 ms rtt or more.
With 10 Mbps, you should be able to get 3-5 Mbps through nested VPNs. I use UDP for all of them, so there's no retransmission chaos. As you add VPNs to the chain, bandwidth doesn't necessarily go down. But rtt increases, of course.