With the covermate 4 it should be metal brkts mounted to the sides and there should also be these metal plates kind of a filler psc that fits between the bracket and the spa skirt itself. Supposedly it helps stabilize the lifter brackets?
In regards to the wind the lift does/should have a lock mechanism to keep it from coming down on your head when windy? And you should be alright with any wind below 15 to 20 least from my own experience in the Pac NW.