It matters not how much your arrow sticks out past your bow at full draw. The only thing that matters is that your arrow is the correct spine and that may mean you need a longer arrow to get it right.
Also, arrow length is very important to gap shooters because the longer the arrow, the shorter the distance for point-on aiming. Gap shooters need arrows to all be the same length in order to achieve consistency in aiming. So, once they find an ideal arrow length that is the correct spine, they stick with that arrow length.
But, basically, it's all about the spine. When you get it right, it doesn't matter if your arrow sticks out a foot or just an inch, as long as you get great arrow flight.