Weightless requires an Oculus Rift DK2 with a Leap Motion controller mounted onto the front of the headset. Are you getting mirrored hands when using that set up?
Sorry it's not working for you. I was going to upload a non-DirectX11 Mac build after seeing your comment but I just looked up the 650M and it supports DX11 so that's not the issue.
Hopefully someone else who's got it working on Mac can chime in...
Thanks for the nice comments!
I'm using Open Broadcasting Software with settings as described here: