For now, if you plan on just shooting field tips/target points your short vanes (not vains or veins) should do just fine. Later on as you replace arrows or need to refletch some you might consider 4" vanes or Blazers (2") to stabilize broadheads. And these should have a helical arrangement. But I wouldn't worry about this for a while. You have more imprtant things to worry about, such as learning how to shoot with good repeatable form and how to tune your bow/arrow setup so that when you do get blades up front they will fly well.

There are many target shooters throughout the world who find that 2" vanes or feathers do an admirable job of guiding an arrow out to 100 yards and more, so I don't know how much I'd be listening to someone telling me they are only good out to 20 yards. Truth is, if you learn how to tune a bow really well there is no need of any kind of fletching if just shooting 20 yards.

Just have fun for a while and don't over think things.