Layout: Full Score vs. Custom Score

Just to confirm my presentiment…

If I in Setup Mode in the right panel Add Full Score Layout I will get a score layout with all instruments ticked and all flows selected.
If I in the same panel Add Custom Score Layout I will get a score layout with no instruments ticked and no flows selected.
Basically it is just starting on two different ends of the same thing. I will in both cases have access to my (Score) Master Pages, also my individually prepared ones?

In contrary, if I Add Instrumental Part Layout I will only have access to my Part Master Pages.
Is this correct?

Can one Propagate a Master Page across from a Score Master Page to a Part Master Page?
I guess, there might be a reason why not?

Thank you for comments.

ps: I know I could figure this all out by try and error possibly

You’re basically right, except that you are not limited to the full score or part master pages in either kind of layout: you can choose between any of the master page sets in your project for any layout, either on the Page Setup page of Layout Options, or in the Master Page Sets panel on the right-hand side in Engrave mode.

Thank you Daniel, being able to share layouts in between is a feature I welcome.
It may sound silly, choosing a layout in Layout Options: I am learning new things every day…
… a predefined layout that is … master page sets