Change size of single staff of multi staff instrument?

I was wondering if it’s possible to change a single staff size of a multi-staff instrument? I have added a third staff above a piano grand staff, and that top staff needs to be small, like an ossia staff, but it’s actually part of the music and should play back (since Dorico does not play notation on ossia staves). Changing the staff size changes all the sizes of all the staves on the piano.

Right now my workaround is to have both the additional staff and the ossia staff notated identically and to remove the extra staff (it will still play back).

Thanks for any advice.

You can’t change the size of a “normal” staff belonging to an instrument. What you can do instead is add another single-staff instrument belonging to another player, and set its size to be whatever you want, then create a brace spanning all three staves in Engrave mode.

Thank you, Daniel. I’ll keep that in mind for the future.