g'day jason,

it would probably come down to how much light you need to maintane say
for plants or light that may be neded in the house. pretty much plants
will grow under anything you put up as it protects them from the worst
of the sun, though roofs that don't let light through may limit plants
to being around the well lit parameter.

they have a carbon fibre translucent or tinted roof now that is
stronger that ulcanite, you can also keep heat build up down by laying
shade cloth under those types of roofs.

my thoughts

len

snipped
--
happy gardening
'it works for me it could work for you,'

"in the end ya' gotta do what ya' gotta do" but consider others and the environment
http://hub.dataline.net.au/~gardnlen/