Using Trekkingnut's suggestion of adapting his "fat tree" suspension setup, I continued to experiment and came up with a workable solution that doesn't seem to beat up the very thin Spectra line on the ULBA like the Garda Hitch did. Photos are attached for reference.
I first do two wraps of the Spectra around an SMC descending ring and slide the ring out of the way. I used one extra wrap because it distributes the load over more surface area of the thin Spectra line but still allows you to slide it easily when tension is released.
I then run the line through a carabiner attached to the tree hugger strap and return the line to the SMC ring.
Rather than lash the line to the ring, as shown in Trekkingnut's video, I found that a Slipped Buntline Hitch is quicker, holds the load nicely and doesn't seem to lock up. A brisk tug exploded it every time after being under load and it held with no slippage. A look elsewhere on the HF site indicated that this knot is recommended for the Warbonnet suspension, so it has a working history.
Depending on the distance between trees, you will have to position the SMC ring on the line to give you adequate room to make adjustments. I found the best way was to slide the ring down to the end of the hammock when packing up. When you next set up, pull the line through the carabiner to roughly the height you want, slide the ring up to within a few inches of the carabiner and tie off the ring with the Slipped Buntline Hitch.
This has been backyard tested but not field tested with a full night of tossing and turning in the hammock, so be cautious. It does seem to work better with the thin Hennessy Spectra lines than the Garda Hitch and still gives you the ability to adjust the suspension quickly with little effort.
I would still opt for the Garda Hitch if using heavier suspension lines such as on the Explorer or Scout because of its ease of use.
I know this is an old post so I'm sorry to revive a dead subject but I recently stumbled upon this thread and I really like this suspension setup using a rap ring with a slipped buntline. How did it work of for you in the long run Ted? Any issues with rope burning or wearing out? Anyone else use this setup successfully?