I cut end of 2 sheets at 45 degrees and then glue with cyano ( on the inside surface )- this gives a longer glue joint which is not aligned straight across the wing. This is ample for sheeting foam wings. ( ie same as joining strip balsa )

If sheeting over ribs then vary angle to ensure the joint straddles at least 2 ribs and then add a strengthening 1/16 sheet doulbler across joint on underside between ribs.

John