Would a 1.37 Carat round with diameter of 7.11 - 7.16 look porportional to an e-ring that is only 1.9 mm width? It is a 6 prong setting. The ring size is 3.5 btw. Her hands are slender and long if that matters.
It depends on what looks good on the person''s hands. As long as the band is well made it shouldn''t pose a problem, but make sure that it''s a well made band if it''s going to be that thin.