Re: Relate to your mind as a clear spacious sky and to the thoughts as clouds.
Dan, it can be done prior to Aikido. It would be very useful. However it cannot be done whilst moving or whilst doing Aikido.
I'm sure many do practice such things before warm up and training. It's a good aid to Aikido but definitely not Aikido as far as I am concerned. You can apply Aikido principles to doing that, yes, but you can't do that whilst doing Aikido. You'll get hit.
So as I said, it's something like a yoga technique, designed to be done in a quiet space without interruption. Without interruption is the difference.