Not considering weight (these might be heavier), do you think something like this would work in a descending ring suspension setup with 1" webbing? Larkshead a pair to a contiuous loop and run the webbing/tree strap through the flat side? It seems like it would work pretty good for cheap: $.75 per d ring.
https://www.shipperssupplies.com/1-d-ring
dring.png
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