Hello BigAkoya
So glad my post made sense! There aren't a lot of pieces that tug at me as much as that gorgy, large pavé pendant!
While I didn't have my large silver pendant with me at the time to compare, it did appear to be the exact size/shape as mine. I've posted some pics below with various pieces, hopefully helpful. I'm not sure why Tiffany is so dimentionally challenged, but it's surely not serving them well!
Maybe try to get dimensions for the currently offered, large silver one if you go that route. Looks to be the same size as mine purchased years back. Regarding alternate chains, I bought my bead chain (with the unusual clasp) as an option, as then I could still easily swap it for the original silk cord. I have found the large starfish slides better (with movement) on the silk cord, and catches a bit on the bead chain. Maybe a different type of silver chain would work better? Have pondered a bit, trying to think of other options, as I find the black (and even the brown cord I purchased later) to be a bit stark on me. I have the same large starfish pendant in yellow gold, and think it would look pretty on a white cord. Still mulling options. Let me know if I can help you further!
smaller pavé pendant and brooch both = size you noted that's currently online
and shown with larger silver pendant = in size to larger pavé pendant
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two pics below are at approx. same scale to give you size reference/comparison
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pics of the silk cord showing how it slides through the pendant,
and how it fastens
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