Spook, for a quick check on a model 4 if you don't have the flaperon rigging blocks:
Take a grease pencil and mark the cord line of the flaperon on the metal inboard flaperon rib. Level the plane to flying attitude and the flaperon cord line should be level for neutral flaperon position. Be sure the stick is centered for neutral ailerons.
Note, for the earlier kitfoxes with the flat bottom flaperons, the bottom of the flaperon should be level.