Wind loading can be a huge force, I would have a real good look at that.
Speaking of having a good look, anyone doing this sort of thing should check out this thread on the Aussie electronics forum
http://www.ozelecforum.com/viewtopic.php?f=33&t=108
As for the second axis, I think most people reckon it's not worth automating, just go out every 2-3 months and adjust them.
Rob