You've got a lot more wood and weight in that canopy than you need. You could have built the whole thing out of plywood and it would have been lighter and stronger. And you wouldn't have needed the plywood stretcher.
Total weight of the canopy is about 10 pounds. main frame is pine furring strips and three 4 foot 1/2" square trim pieces left from another project the wrap is 5/16 lauan ply came in 2' X 4' sheets (all they had available).
If I used 1/4 ply it would have been heavier then what I have and with out a table saw cutting it to size would have been a pain in the rear for me. Don't know about the big box lumber dept's in your area but over here finding some one in the lumber department is a rarity let alone someone that can use the panel saw and then can get the measurement correct on top of all that I'll take my chances on my own. Just had a 4x8 sheet of maple cut for me the other day 30 min to find the guy who had the codes to run the saw then he took ten min trying to figure out that 4' was the center of the 4x8 panel. If I could have fit the whole sheet in my car I wouldn't have waited at all but 4x6 is the largest I can carry in my car. Was so tempted to just buy a cordless circular saw and cut in the parking lot then return the saw would have taken just as long as looking for the lumber guy.