I noticed that Evazote doesn't slip much at all on my hammock's ripstop. So I made a pad layer that doesn't slip. Joined 2 1/8" thick 20"x60" Evazote pads along their long edge, put a layer of insul-brite on top of that, and covered the top with a layer of DWR rip-stop. Sewed along the edges. The top is rip-stop, the bottom exposed Evazote. That pad stays put, inside.
On your down hammock it appears that the stitching crosses the main stress line at right angles. That's good data, because that's the concern with sewing on a pad pocket on a bridge.