Hi all, as the title says I have a gap between the stairs and wall which is about 6mm. I know I can use quadrant bead to block this gap on the straight section but the top of the stairs is curved ( see photos).
What would be the best way to block this off on the curved section, 6mm seems too much to fill with caulk.
Thanks in advance.

Top view :

What would be the best way to block this off on the curved section, 6mm seems too much to fill with caulk.
Thanks in advance.

Top view :
