Ok, just back from my Dyneema X Gridstop strap test.- Using 2 SMC rings attached to each end of the hammock and one end with my regular webbing strap and the other with the Dyneema strap. Straps were cinched tight with a slipprey half hitch as a security knot to prevent slip though the rings. About a foot of strap between the tree and the rings at both ends. HH Hyperlight Backpacker A-sym hammock.
Gentle sitting bounce test- initially Dyneema stretches. Retighten and bounce tested again. Still stretching a little, but note that one of the white spectra threads has broken. Retighten and bounce test again. Again very minimal stretch, but another white spectra thread is broken. Snug up the Dyneema strap and do fourth bounce test and go to ground with failure of the Dyneema strap at the rings. The fabric completely torn in two. All of my box-X stitching to join the two strips and to make a loop at one end held with no sign of failure.
It looks like individual spectra threads were stressed to failure with each bounce test and eventually there were not enough to hold it. Something I might of predicted, but where is the fun in that.
Looks like I may have to try Cuben next. I think if I can laminate several layers that would be good. However, the Cuben will have to wait until I can get the financing arranged.
Actually, I was thinking, as Dutch suggested, that some fabric fanned out around the tree would protect the tree and distribute weight better than webbing. I was also thinking what if one was to bunch that fabric up at the ends, knot it and tie regular webbing or spectra line to each end (yeah, like a miniature hammock). Would that work? Could you save weight? Food for thought.
P.S. Thanks to everyone for your thoughts and help.