Ok, so I hard wired my HR44, then used the coax and splitter for the GenieGo (no Ethernet there). I gave my GenieGo a static IP via manual MAC address DHCP reservation and then forwarded 8082-8083. It was all working for a little while, but now my Genie regularly says Not Connected when using my Mac's Genie app. I can however ping the IP of the GenieGo, and I've rebooted the GenieGo and the HR44 a couple of times.
I've seen it work for a little while, but without any config change, it has decided to not work anymore. I hope the reliability is better than this. I am a network engineer, so in terms of IP addressing, DHCP, port forwarding, etc. I'm an expert.