Shift up OttavaBracket

[Paolo Prete]

Hello.

Please consider this example:

{{ \ottava #1 c'''' c'''' c'''' c'''' \ottava #0 }}

How can I shift up the ottava bracket exactly TWO staff spaces above its calculated position?

Both:

\override Staff.OttavaBracket.Y-offset = ...  and  \override Staff.OttavaBracket.staff-padding = ... don't seem to be the right way to achieve this

Should I use some spanner, like I can do with dynamics?

Thanks,

P