Thanks Roger, that does indeed clear things up.
For background, I maintain the bitcoinj project which is a widely used Java Bitcoin implementation. We are planning on bundling the Orchid Tor client and switching on Tor by default for Bitcoin wallets that are based on this library, if we can. We'll see how it goes but if the UX impact is not too bad then we might be adding approximately 750,000 to 1M clients after the update fully rolls out everywhere (which would take a while). About half a million of those are Androids that would be waking up at least every 24 hours and sometimes more frequently.
I guess we can tweak Orchid so that it uses port 8333 in the policy rather than the exit flag for selection of its exit nodes. Should not be difficult.
I've looked at the bandwidth graphs and see that since September Tor has been adding more bandwidth capacity than usage, and Bitcoin SPV is low bandwidth anyway so that seems fine. Though I'm curious what happened in September - correlated with Snowden revealing that Tor wasn't cracked yet? But, I couldn't find any graphs of CPU capacity. Seems like the impact of lots of Bitcoin wallets building circuits would mostly be on the CPU side rather than the bandwidth side. Orchid supports NTor so I'm hopeful the impact would be fairly low, perhaps even lost in the noise.
If you have any thoughts, I'd be happy to hear them.