Hi Jarrod,
The benches look super!
The Shade Sail and the light concept is very very good.
Im a manufacturer of Shade Sails, im a little hesitant on the idea of actual Shade Cloth Material. Could just be me reading into the thread a little too deeply. But be mindful of the amount of wind and rain load on Shade Cloth material. I would advise against using actual Shade Sail Cloth. Too heavy, and the wind load rating could be too high for your structure, plus, most of the fabrics have a shade rating of 90%+ (so it wont let much light through at all). The most important advice i can give though is, put some run off on the material (slope). We generally allow 1m of fall over a 5m spanse. From the pictures it looks as though the peak is in the middle. I would try and have the sail cloth falling at least 60mm and probably more like 80 or 90 mm, the more the better. The quicker you can have the rain water run off the cloth, the longer the material will last, and the longer it will remain firm over the spanse.
Again i may have read into the term Shade Sail Cloth a little too deeply. I would probably advise using some of the 30% Shade "Mesh" you can get from the hardware store. The same principle would apply above.
Love the benches and sorry for putting my

in if you already knew the above.
Dave