Help Choosing Loose Emerald Cut Diamond For East West Setting

[ememeralding]

Hello! I was hoping for any help finding and choosing a 2ct ish emerald cut diamond. I am planning on setting it locally with David Klass. But if anyone also has experience with him sourcing the main stone as well as setting it, that would be amazing. The ring will be east west with side stones so I am looking for around the 1.35-1.45 ratio. I have been reading up on the ideal percentages and where those numbers should be on the certificate but I cannot seem to trust my choices. The photos and videos all seem great and I cannot tell what diamonds have windowing or extinctions from them or what things to look for to know what is a good cut. I've read that Brian Gavin and Whiteflash diamonds are cut great but you can get just as beautiful ones for much cheaper. Any guidance would be amazing! Thank you!