Here are two of the new GTU rings and the old stuff. Note that there is some fraying even though I tried to minimize it. I have discovered that Western Pacific Tradings GTU frays more than Gore GFO or Duramx Ultra-X. GFO and Ultra-X barely fray at all.
Perhaps, to prevent fraying with GTU, you could heat up a little wax in a bowl and as soon as you cut the ring dip the ends in the wax like whipping a line. There is actually a fair amount man-handling, of the rings, between the time when they are cut and inserted and some measure of fray prevention should be attempted when using Western Pacific Trading GTU or just use GFO or Ultra-X.