#7 - This is very good, and has been ranked #1. It may still go back to #1. The discussions have been that the wave also looks like a moon. That has it's advantages too, but to some it looks more like a moon than a wave.
#58, #61 - These are improvements over #50. #50 felt a little off balanced but you're working on addressing that by putting the wave coming up on the left as well. Somehow the shading is feeling a bit flat. I'm not sure how else to put it. Maybe some of the 3D style you did on #5 would help. I know I steered you away from the 3D, but the image has also changed since then & I think it might help.
I think I like #61 better than #58, by removing that inner circle.