I added the nutplates, primed, painted and mounted the purge valve bracket. Once I have smaller Adel clamps, I'll remove the rubber lining and clamp the shroud much firmer to avoid slipping with the engine vibration, particularly lateral vibration (as is common with a horizontally opposed engine).
Later I'll add a bracket with redundant springs to ensure the purge valve remains in the right position in the event of cable failure or shroud movement.