Depending on where you are in the evolution of a kit builder (or ARFer, for that matter), a 1/16" gap is about par for the course. I've flown lots of planes with that much gap, and most planes I see at the fields have that much gap or more. However, best practice is to seal the gap with monokote or ultracote strips. Doing so will give you better effectiveness of ailerons, smoother flying. Not doing so is no disaster, but as your flying gets better you'll have more incentive to do it.