2013 Grand Scenic Spare wheel

I have ordered a spare wheel carrier for my GS and I am debating the space saver v full size spare. My only concern with a full size spare (205/60/16) is the ground clearance when fully laden. Renault spec the laden ground clearance as >120mm assuming from my crude measurements the spare would sit approx. 75mm below the wheel well/ rear bumper this would leave a ground clearance of approx. 45mm? Has anyone who has fitted a full size spare experienced and issues with ground clearance, speed humps etc.? If I follow the space saver route I'm guessing it will be a 135/90/16 as this is the closest circumference to the full size wheels on the car?

Thanks for any advise you can give me.