It's good to see someone talking about a large amount of files, and highlighting that 8GB RAM is required for this amount of data.
I have a question though, are you only using Windows based machines? We're currently sync around half the files you have (2TB), mainly on OSX but we seem to be hitting some temporary issues with Sync picking up and trying to reconcile com.apple.resourcefork files.
I've read that i can comment this out in the StreamsList file to stop this from happening but i'm not sure if it's safe to do so. Wondering if you've come across something similar?