I think that this tiara (if it still exists) would suit very nicely with the Delhi Durbar emerald necklace (which has cabochon emeralds, like the Greville tiara) than with the Greville emerald necklace (which has facetted emeralds).
I have made the following photomontage, trying to depict how the pairing of the Greville emerald tiara and of the Delhi Durbar necklace would look like:
I hope we will soon have an occasion to see this combination for real, and not just on photomontages!