not really practical
There's no getting around the wind on this one. Even flat it's a little dicey. We get a lot of out of the blue gusts around here so even a calm day is no guarantee that I'll be safe. A person and a bike just don't weight enough compared to the potential wind load on something with that much surface. Short of having it delivered, If you can design your project to use 2' x 8' s that might be safer. Home Despot will give you two cuts on your plywood without charging you anything.