The fabric is very light. Much lighter than Icarex. It does stretch a bit but since I am using it for gliders that is not an issue for me. It is a bugger to sew, easily ripped, and you only get one go with DS tape. It is a bit tricksy to work with and I think it is not cheap. If I was looking for very light weight material for a full size stunter I would think that very light grade Cuban would be what I would try. Again not cheap but you can sew it.
For SSUL kites i reckon the rods, fittings, sail pockets and reinforcements are the way to get a light kite. If your really keen after you pare all that down the next step is sail material.