I love Pittosporums, but I understand they do best close to the ocean, and in sandier or siltier soil rather than in heavy clay, Sunset zones 24 & 23. 'Marjorie Channon' makes a very nice screen, or other tenuifolium hybrids, like Pittosporum tenuifolium 'Silver Star'. (Monrovia is selling it as 'Emerald Wave'.) 'Silver Sheen' makes an airy tree, but is too large for your purpose. Look around your neighborhood and see if there are any growing. They are lovely plants but can be fussy in conditions they do not like.

'Emerald Wave' now big enough to peek over my wall:
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Come to think of it, my neighbor has a Hakea that's quite lovely, airy but substantial enough, and drought-heat tolerant. It's more airy than the photo shows...
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How tall do you want it to be? I'm planting a row of Iceberg roses in front of my chain link and a row of nandina behind. The roses get about six or seven feet tall here in Simi Valley.
Renee

Hop Bush (Dodonaea viscosa) - you can shape it to be a tree or bush, it grows quick and is very drought tolerant. Also changes colors from green to a purple. They are more airy than other privacy hedges, but give enough privacy when needed.