Originally Posted by brookfieldangler
Besides, when you are casting into really windy conditions and/or big flies, the extra power generated by having your thumb on top can really be an asset. Learning this technique will make you a more versatile angler.
I know less about the fly cast mechanics than most, but have found the above to be true. If I need to make a powerful move with the rod or really nail a roll cast, the thumb on top makes a significant difference for me...and if I'm throwing an 8 or 9wt with a heavy head (like for stripers in the delta) thumb on top is much better and saves my shoulder by end of day. Maybe that has to do with thumb on top helping me keep the rod from falling to a sidearm motion...?? $.02