The product we use for our canopy construction is called “Alu-lite” made here in New Zealand by Awnings and covers in Tauranga. The framing is box section (rectangular shaped, not round poles) high quality aluminum colour powder-coated to the colour of your choice. We can make them with either a flat (mono slope) or arched rafter style. Every job is custom made. I will come to your site discus your requirements use all my experience and design advise to figure out the best solution to meet your needs.