I've forwarded ports 3074, 3478, 3479, 3658, and 4500 and went ahead and disable my firewall.
Since forwarding these ports I now see an open nat and I've hosted 2 games, both games ended after only a few minutes with a BO2 server disconnection. This was never an issue when hosting as moderate with no ports forwarded.
Also no one else has been the host yet. before I come back to check this I'll have restarted my computer and had another host for me.