ORIGINAL: tacx
Smallest gap possible and still maintaining full movement.
Yes. You do not want any binding.
Then, as another modeler suggested, seal the gap, but I would add, only if the plane is 60 size or larger, or if it is smaller but very fast. A smaller 3D plane will possibly benefit from sealed gaps as well.
If electric, Scotch tape will do nicely, if nitro or gas, use clear or color matching covering and a trim iron. Both Monocote and Ultracote come in clear. Always be sure to give the surface full deflection when applying the seal to the gap so as not to cause restriction.
With properly installed hinges, and sealed gaps, flutter or hinge failure is almost never the cause of the accident.