This tensioner pulley is supposed to be specific to the Series II L67, which would include you. It'* probably the same diameter shaft, you just hold it on with torx, and others use hex. This was designed specifically to put you back in the center of travel on the tensioner, and still have the benefit of a fuller 'wrap' on the SC pulley.
I called ZZperformance to see if it would work with the pulley ratios I was playing with on a Series 1. It looks like it'll work, so I'm gonna try it. My pulley is coming with a new belt, but this way I get to try something new for the 'team', and maybe gain a little benefit from it.