Here are what the three diameters look like in the space (50”, 35”, 27” in that order)

I would definitely go with the largest (first photo). I love the bubble lamps and have wanted one for years, but DH is not a fan. I would get the round one for myself, but we have only 8' ceilings. Sigh

I also think the 50” is right for your room.

I agree with chispa to mock it up. But my instinct is go as big as you can -- that room is huge. ffpalms is spot on. I love how that saucer looks!

@cyn427 (z. 7, N. VA) Oh, I’m sure my hubby will have something to say about it too LOL

Thanks for all the input!

My first instinct was the XL too, but then I realized my kitchen table is 48” and couldn’t imagine that floating above my living room. It seemed so big that I second guessed myself. I’m very glad to have all the concensus!

Off to make a huge cardboard circle haha

I'd actually do a grouping of Nelson bubble lights instead of just one, especially for a room that large with high ceilings. Funny, I was staying at a hotel recently and they had a great grouping that I took a picture of, below:

Now, you don't have to do this many, but I love the effect of multiples. I'd go with an odd number, like 5. Hang them at different heights like they did here.

I always like them best hung in groups

I would also do a grouping, one large is going to look very odd, it did in the mock up below.

BTW not a huge space only tall.You have think volume of the space so 3 hung at different levels and all different is what I would do.

I think you can do something more interesting than the Nelson Fixtures

Keep in mind the fan in the space was probably 54" in diameter

An open fixture like the ones posted below would be visually interesting in the space.