I agree that Hans' suggestion would make a (more) successful and elegant design - especially with upright pear-shaped pearls between the diamond elements. Not a very big tiara, but an elegant-looking one, a bit similar to Princess Benedikte of Denmark's pearl and diamond tiara.

Unfortunately, I fear this is not possible, as the Wessex tiara has already been altered in 2019 (for the US State visit to the UK), when a lateral part of each side element was removed to bring the lateral anthemions closer to the two central elements. I don't know if the removed elements were saved, or if their diamonds were reset in the new base of the tiara.
I think it was the last time the Wessex tiara was publicly seen (please, correct me if I’m wrong about this).