What do you define as a large network? And what would efficient mean for a network that size?
100,000+ nodes
efficient would mean close to optimal redundancy
still need to work out what sort of probability distribution there will be so I am not sure what "optimal" is yet
How many public/private nodes?
this depends on the users. I am counting each computer as a node and most will probably have a loopback privacy server along with the private node, then the 100+ public privacyservers, so that is 1000 clients for the 100+ privacyservers. sounds like a lot, but UDP processing will be fast and network packets are so slow compared to CPU, I dont think it will be an issue. RAM will probably be the limiting factor, but even if things have to swap to HDD it could be fast enough