Ah I think youve already said the pedestal sits flat in which case you have to put a washer of measured and sufficient thickness to ensure that theres clearance to measure as in the drawing. There ithe washer is item 4 sitting between the gear and bush but it could be put, as has been suggested, on top of the gear so the pedestal sits on it. However with both positions I imagine theres a risk of it slipping off and falling inside the engine😩