@taro , the doubles program has actually worked "better"so far but I have done a round of 2.0 with a single bell in the past and it was effective! I think you'll make great gains with either version.
@Mark Limbaga hit on a point as to how this came about. (Although I certainly wouldn't say I was courageous, ?) ... I attempted some of Geoff's "singles" programs as doubles programs and he gave me a thumbs up to try them. They came from "Kettlebell Express" where the original Giant program came from. On my radar after the c+p programs is the "double king sized killer", a snatch protocol. I have done it effectively as a single bell program and will try it with doubles.