Lol, I feel like its sorta funny because you're talking about cushions and emeralds... and that's exactly what my bf & I have been lookign at. Emeralds are so classy and elegant, they really have a timeless and unique quality to them. I have always admired them but didn't think I'd want one as an e-ring and my bf picked one out for me to try on and it was stunning! I think the size preferences depends on you, I was happy with a 1.5 because I don't like big jewelry for every day stuff but seriously I sat with a cushion on one hand and the emerald on the other and couldn't decide! I was like sparkle vs. elegance and I couldn't decide which I liked more... so hard.
I think you'll be happy with either choice, what I didn't like was that the ec i tried on did not sit flush with a wedding band... but it seems like you've found one that does. Have you looked at asscher cut diamonds? There's the branded royal asscher and then just generic ones, square emeralds, those are really pretty too, but I have yet to try one of those on, maybe next week in nyc when we hit a few more jewelers.