There are 2 things that keep a flyline in the air loop shape and line speed loop shape is total up to you,longer lever means you can generate more line speed That is the only reason a 15' two hander cast a greater distance than a 10 footer. BUT INMO there are far fewer good 10 footer to choose from. than 9 foot rods.Most of my go to rods are 10 ft. for all aplacations. it is not right or wrong it is simply what I like. It would prefer to use fire retardent as fly floatant so my go to rods are FAST too.

Rich