I use 6mm for the cables except the top two on the pull up side which I use 10mm.
I don't know how strong the winds are in them there Adelaid hills but for me 42' radius is not enough for that height. It works for 64' but 84 was a disaster.
http://www.anotherpower.com/gallery/allans-place/shit_happens_small_001
Woof 21 feet is the length in the old measurements (we went metric in 1966) for pipe in OZ. Having the guys at the joins works for me, unless the joins are very ridgid it makes for a more stable.
allan down under
A life lived in fear is a life half lived.
