Actually, I'm willing to read the opinion of our fellow developers!
I normally have a general event sheet with the core gameplay functions so that all levels (layouts) are referenced to it.
Tutorials, menus, or cutscenes are handled with other event sheets. If a a tutorial is similar to another menu/or cutscene, then I would implement just one event sheet to handle them.
I wouldn't recommend having an event sheet per layout if those layouts perform similar functions.
Memory/resourceswise I don't know if having more event sheets hinders the performance of your project. If there is someone who knows the answer to this question, it will be appreciated!
Let us know what you're working on! If you need help, just ask!