I'm going to bump you up. No one responded because you didn't post a picture. That is going to be necessary to get answers to your question. Personally, the designation of "Tiffany" could mean so many different things, I'd have no idea what yours looks like.

I agree that a photo would be really helpful. That said though, I had a very nice stained glass fixture in my kitchen over the table (in my previous house) and when adding pendants for over the island, I did chose something with similar finish and shape. It went really well so I would think that might be something to keep in mind. At least the finish and perhaps the feel of the fixture should matter. Linear seems to be more modern but maybe a vintagey linear fixture would mesh.

long winded way to say please post a pic.