Staff size-custom

I have several flows where instrument A appears in every flow, while instruments B, C, and D are different in each one.

Is there a way to change the staff size of B, C, and D across all flows at once, or do I have to select each flow and change it individually?

Instrument A needs to stay at the default staff size, so I only want to adjust the staff size of the other instruments.

Check out this video, does it help? https://www.youtube.com/shorts/MhySg73oeGI

Thanks.

Do I have to do this for each flow individually? Is there a way to do them all at once?

I guess you have to do it per flow. I am far from a super user, in fact I can’t stand the whole program, but I watch these videos and some of them are quite useful.