farminred,

The way I did this was cut the hinge-slots in both components (e.g. trailing-edge and ailerons) when still uncovered, then cover one side (e.g. ailerons) and use the other (e.g. trailinb edge) as the measure-stick to find the slots again, which you then cut through the covering . Then you repeat the process the other way around....

Worked like a charm

Good Luck!