deadstock

i'm a new GS owner and I am putting on some wheels that have a 5x120 lug pattern. Do any of you guys know how thick of an adapter I need to keep the wheel studs from hitting the wheel. I heard a 1 inch thick adapter was ok but wanted to make sure? It seems 1.5 inch thick adapter is more common. I want to go as thin as possible so i still have wheel clearance. Any info would be helpful also post pics if you have adapters on your ride and list the specs on the adapter. Thanks!