I agree with Bamboozle, let the fish tell you what works. I fish wet flies almost exclusively and every time I fish it changes. Sometimes the movement of the fly by the current is all that's needed, sometimes the smallies hit it at the bottom end of the drift, other times they want to hit it when you slowly bring it back up stream and sometimes they hit it when you bring it back upstream very quickly. Also remember what you see and what the fish thinks it sees is also different.