I tried using existing holes for a tie down when there is threatening weather but nothing seemed to work being that the legs attach by two points and not three to form a triangle. Putting too much tension on bungees or ropes would cause the whole assembly to bend one way or the other.
I came up with this idea which will let me drive stakes right at the bottom of the legs and secure it from there rather than at the panels.
The legs attach to the bottom brace with clevis pins so it's easy and quick set up/down.
Here's what it looks like assembled
A close up of the attachment point
And for securing it to a stake, a simple piece of rope that you drive a stake through.