In some of my recent research notes, I make a case that the shorter averages are more likely to correspond to actual trends in the markets. I look at the 5-day cross of the 10-day.
Flipping through last week's Journal, I can see that this crossover is only really significant in two pairs; CAD/JPY and GBP/EUR. It's been acting like a contrarian indicator with CAD/JPY and like a regular trend following indicator with GBP/EUR.
So I don't think there's really a single answer to your question. If one "big dog" uses a particular setting for an average, and another "big dog" uses a different setting, they might kind of be cancelling each other out.
The only thing to do is to see how the market behaves as a result of all the trading done by all the dogs (and cats of course).