@norriemac  I think I would glue the 3mm olive wood onto the headstock before gluing the fretboard in place. Then flatten off the olive wood down to level with the top face of the neck where the nut is going…   Read more»

Thank you Russ, Robin & tv1,  That’s put my mind at ease. I’ve still to glue the fretboard anyway so will work on that and in the meantime I will practise blending on scrap before doing anything with the headstock….   Read more»