Optimization suggestion regarding Document objects?

My app will probably allow the user to have multiple documents open at once (or seemingly at once) with a typical tabbed interface.

I read in the docs that I should create one Language instance per type, and reuse the language instances across all SyntaxEditor objects that need them.

I'm wondering also, is it suggested to keep a separate list of Document objects, say one per open file, and assign the SyntaxEditor.Document property on the fly? In other words, I'd have only one SyntaxEditor object in the application, but one Document object per tab; and then I would set the SyntaxEditor.Document property when a tab is selected?

Or is having many SyntaxEditor objects usually not that much of a worry?

I'm planning on trying it both ways and watching the memory usage in Task Manager, but I was wondering if there's any rule of thumb based on previous experience?

Thanks!
Jeff