I plan to build some kind of structure for the slab with enough height to allow me to put the push mower over the rider's shroud. That way, I can store it lower and prevent me effing up my shoulder, like I did a week ago Sunday. I haven't decided on the exterior, but I think T-111 may be a possibility- that will make adding vents easy. Having shrink-wrapped and uncovered a lot of boats, I know that moisture inside of a cover is a big problem. I may add a fan on a timer to it, to circulate the air.