Thanks for posting the video!
To be 100% tied in at all times I suspect you would need 2nd tether.
This year I want to do some preset ladder stick / lifeline setups and just carry my lonewolf alpha with me and attach it to the tree when I climb up so I really need to have a lineman's belt for this approach. I think I have seen someone on archerytalk with a lineman's setup on their RC harness.