Hi Scott, I have attached some photos of our recent shed build for reference, very similar in size to yours at 10m wide x 13m deep, 3m high walls, 15 degree pitch, I plan to install an overhead 2 post hoist, the generic brand hoist at our previous home worked well, installed it myself but had it checked over by a qualified inspector doing his rounds, the clearance to the roof is 3.9m at the post locations, concrete was thickened to suit, I also plan to put together a build trolley for the GT40 sometime soon, I feel both will be handy. All the best with the build, Derek
