I love the design of flipping end over end and will to try and suggest a possible answer that may or may not work is, using the video as a reference.
It may be possible to rotate the robot frame CW around the upper arm and at the same time rotate the lower arm CCW. This will have to done with great care so that as the load is changed from the lower to upper arm you robot doesn't just lose it's grip and fall off
Aside the 54 " possible problem you need to watch out for differences in height from one rung to the next which according to rules may be up to 1/4 inch but I would allow for at least 3 inches either way.