My pal Mark Ward has a wonderful piece at the Logos Word by Word blog, where he models exceptionally wise usage of commentaries to help him answer a specific question: What does it mean that Leah’s eyes were weak (Gen 29:16-17)? Ward is not so arrogant as to ignore the commentaries altogether, and he is not so slavish as to read only one commentary and accept the conclusions without inspection. He examines many commentaries, explores the nature of a variety of conclusions, and he takes the debate with him right back into the text to make up his own mind.
With something as simple as Leah’s doe-eyes, here’s what I would do: I’d land. I’d land without telling everybody where I’d flown. I’d stick with the intuitive—to me—opposition the text sets up, in which “weak eyes” are contrasted with Rachel’s beauty. And I’d appeal back to my gut feeling as someone who loves and knows language; I’d explain the text as an idiom communicating, in a delicate way, that Leah wasn’t quite the looker Rachel was.
His conclusion is rather straightforward, but the road he traveled to get there is deeply instructive. I commend it to you as a path you ought to follow him on when you have similar questions. For further reflection on this sort of methodology when using commentaries, see my ten commandments for commentary usage and the explanatory posts that have followed.