If you want a light rope, you should look at the weight per metre. Here the Edelrid Skimmer Eco Dry 7.1 and the Beal Gully 7.3 Golden Dry are ahead, closely followed by the Edelweiss 7.8 Elite. The Edelweiss, however, only has half-rope certification (just like the CT Tour 8.3), the Beal and the Edelrid have half and twin rope certification, as does the somewhat heavier Mammut 8.0 Alpine Dry...