I think it's better to not be absolutely symmetrical in that kind of composition. The slight unbalance adds a little tension to the image and strengthens it quite a bit.
In practice it's almost impossible to get total symmetry - there's almost always *something* that's off - in which case deliberately going for near-symmetry is probably the better option.
I do love the image tho': echoes of nature replicated in steel and glass. An image crying out for Lith treatment I wonder?