Size doesn't matter. It is all in the technique.
I agree with Ken!
I like to tell a Lefty Kreh story about a friend's question about rod length.
A friend was having trouble fly casting from a float tube and thought he needed a longer fly rod. He was at a a fly fishing Expo and took the opportunity to ask Lefty the question.
Lefty took the tip section from a 4pc fly rod, sat down on the floor and cast the entire fly line!
Don't over think the fly rod - think about the making the fly line do what you want it to do - it's all about line control.
G/