First of all, thank you! So glad S&B had you speaking in tongues ;)
As for your question… Hmm, I know the book has some rather lengthy physical descriptions of characters like Zoya, Genya, and Ivan because they’ve been quoted in some gorgeous fanart. I think the Darkling got his due, too. (In fact, I kind of cringe at how often I mentioned his eyes.)
That said, I think you’re right. I don’t get into the specifics of hair color, eye color, etc. with some of the characters. I guess I sometimes like to rely on impressions rather than specific physical traits, like when Ana Kuya describes Alina as “pale and sour, like a glass of milk that’s turned.” But definitely something to think about!