I agree cool weather won't need shade netting this time of the year. Lettuce, kale, cabbages should be good in full sun till you hit the 70's. It is true that in summer when it gets warmer lettuce will grow very fast. Tipburn is a physiological disorder because lettuce will grow so fast that it cannot get enough calcium transported to the top so it tip burns. The solution to that is to get tip burn resistant varieties and harvest before the lettuce starts to head up which is when it is the most vulnerable so instead of 6 weeks, some lettuce may be ready 3 weeks from transplant. In summer I plant heat resistant lettuce, more red lettuce, and instead of planting in full sun, I plant the lettuce under my trees or you could plant on the east side of the house or garden between taller plants that will give the lettuce some afternoon shade.
The warm season crops beans, tomatoes, peppers, squash want it to be in the 70's and 80's. Peppers and tomatoes though start balking when the temperature approaches 90 and you need to have good leaf cover to prevent some sun scald on fruit. Heat resistant varieties help here and maybe some summer shading and misting to cool the plants will help.
I have used bug and bird netting for pests. I only use shade cloth on my orchids and anthuriums. If you lived in Arizona or Texas where the summers get wickedly hot, shade cloth could help.
Happy gardening in Hawaii. Gardens are where people grow.