There is no port which is guaranteed to be open I'm afraid. By definition the NAT/firewall combo in a home hub will prevent any
unsolicited (i.e. unexpected) packets from crossing into your internal network.
I can only suggest following a video tutorial such as this:
to make sure you've done all your port forwarding correctly. Clear out everything you've got in there and start fresh, testing with shields-up along the way. Be methodical and precise, taking each step at a time and you should be able to resolve your issue.
Apologies I can't offer any more assistance, I feel I'd have to physically see the setup and walk you through it to be sure. Obviously if you could take some screenshots of your process and then if it doesn't work you can upload them and we'll see what might be wrong.