Hi! I´m also jumping an Sabre2. It´s my first own Canopy. At the beginning I always had closed end cells.
Because of the zero Canopy it was very difficult for me to pack it and i watched this Video: http://www.youtube.com/watch?v=jqNsFPbKIw8 Since I do it the same way specially at minute 6.51 I didn´t had closed end cells any more. I have now about 150 Jumps on my Sabre2 190 and at the last 100 jumps I didn´t had closed endcells any more! I´m not really sure why, but only the part at minute 6.51 changed, everything else i did the same way before to. Sorry, but my english is not the best