Use Different Project Preferences files

I am working on different projects simultaneously. I need different Preference files.

I am wondering if I save my modified Preferences:
Tools --> Options --> Manage (button - lower left corner) --> Save Preferences --> name it modified.prefs

Then select Defaults to reset preferences to the initial “brand new out of the virtual box” settings for a specific project. Then save the defaults as a Preference.

Will Manage --> Load Preferences --> select modified.prefs file? I am assuming that’s how it works.

It wasn’t clear “to me” in the manual, so I wanted to verify.

Next Question:
Do the preferences then remain across all projects or just for the current project, where I need the defaut settings? I am guessing the preferences go across all projects and I will need to load the preferences file, when I switch to another project.