Just wondering, then Ill leave you alone and get back to tending my own sheep.
1) How wide will it be?
2) will the roof be flat or pitched? If you are using trusses, what style?
3) is there a code restriction that limits the height?
4) will there be provisions to allow it to be enclosed should you ever desire?
5) design provisions , and adequate height, for a future overhead door should you ever want one?
6) is it feasible to make provisions for you to dump the holding tanks? All that takes is a 4 line attached to the existing system. This is super convenient.
These issues are readily, and fairly inexpensively, resolved up front rather than later on.
Enjoy your project.