I've seen where a sail canopy in high winds has snapped 6x6 posts. Buckets filled w/ concrete are just going to get dragged around in a storm and maybe even get your building on the 6 o'clock news. Pergola with open rafters is a better direction.

Thank you. How would you secure the open rafter pergola?

Since it's a rental I don't know how much you're looking to spend, but if you go with a company like Fifthroom they can probably advise you. I leave rooftop projects to people smarter than me, so I'm not much help there.

Thank you... It's a long term lease for a veteran's home, and we're going to donate our time and any materials so we want it to be nice.