Db,
In the chat you posted " Remember that the 50s are just signs of strength or weakness. What is more important is the strength or weakness itself."
In order to define strength and weakness without using the 50%s should I then first focus on the waves and the exhaustion of the movements? The tipping point concept you mentioned today?
You can use the 50% levels, but remember that they are there as a measure of strength or weakness, not as yes/no indicators. For example, if price rises and breaches the 50% level then falls back below, that's as much a failure as if it had never breached the level in the first place.
If you require a visual, imagine pushing a car up an incline. Your first effort may get you quite some distance, but each subsequent push is going to cover less ground until you reach the crest and the car starts moving down the other side on its own momentum. Simple-minded, perhaps, but more accurate than one might expect.