I didn't record the exact stats from WANOS wan0, but did glance at them at the time and they were in the similar (minus the overhead from the VPN, but that's been fairly consistent). I would redo the test, but this has actually been going on for days (did the uncompressed test before I actually posted the original question) and it would take a while to reproduce the exact test again.
I'm setting up a new lab environment to test this further in a more scientific approach. Going to take the VPN and routers out of the equation, and also going to make sure there is no other traffic besides the replica traffic.
As for PLR, my understanding was that it only helps in scenarios where there is packet loss, which as best I can tell there was none (and the WAN in this case was just a 100Mbps network connection between routers so I was in full control of that). Does PLR provide additional compression/dedup benefits? If so, how do I enable it?
I'm already liking this product so it won't be long before I pitch getting plus licenses, but for now I'll just stick with express for the experiments (I can always put a limiter at the Hyper-V level to keep the flow of traffic the same between all tests).