Vane? Try two CM7703 Bent to suit your needs. One on each adjuster at the bow. Other than that. One off the front of the mast would work. We used to have an adapter for that, but looks like its not available any longer.

Mast rotation is a line tied at a cleat on the boom that then runs to the rotater arm and back to the boom cleat. Basic rotation: Rotate to near (pointing at) the shrouds upwind and 90 degrees plus downwind. I haven't raced the 17 in awhile, there is likely to be more fine tuning.