I wish I could help Annette but your Brisbane weather seems to be much milder than what we have here. We normally use 50% shade for our mature plants and 75% for our seedlings and young plants. Most orchids can tolerate morning sun to 11 am and afternoon sun after 5 pm here, so the shade we provide will have to take that into consideration. I don't know if that helps. I'm sure some of our Aussie members will have better suggestions.