I would use a multi-pronged approach and test the two approaches you mentioned as well as Ehlers' roofing filter tuned to the cycle period. Ehlers recommends a signal line for triggering trades which is simply the indicator crossing itself delayed by one or two bars.

I would also test Ehlers' adaptive RSI and Stochastic tuned to the detected cycle.

It seems to me that these approaches give some very good signals and some very bad ones. But knowing a little more than we currently do about tradeable cycles, I think we could filter at least some of these bad signals. Whether that is enough to make such a system profitable is another question entirely.