Wanting to build a garage (Need advice)

Hello, and congratulations on your upcoming build. I've built my garage with a 13ft ceiling and 9 ft sidewalls. This is more the adequate for my two-post lift. I would recommend no less than 12ft ceilings for a lift. The ten ft sidewalls are a bonus. I would go with the 24 inch on center rafters with plywood sheeting. If you have any other questions or concerns about your garage, let me know. Hope this helps, Christopher.