Maybe this is not the answer you are waiting for, but I hope this helps a little:

It's best to find your dream signs from your dreams. People, places, actions that are frequent in your dreams. Then you find those in waking life and do RC.

I personally don't rely on dream signs. There is a chance that none of them shows up in your dream and then you loose your chance to become lucid in that dream. I practice daytime awareness. It will help you get lucid in any situation, even when your dream sign doesn't show up.
happy dreams