Not often, no, and when I do, it usually comes after the fact. Having a casting in mind from the start is rare.
. . . and now that I think about it, one other case where I know I had a casting from the beginning was Paul Bettany as Jack Ellin (In Ashes Lie). And I also feel like I have a better physical sense of Jack than I do of many other characters, so I may be on to something here.
(I also had Amr Waked cast as Suhail before I wrote him in Voyage of the Basilisk, but that came via a Google Image search, not via seeing Waked in a lot of roles. I wanted a good visual reference when I described Suhail because, quite frankly, Arabic men are not common in my daily life, and I wanted to be sure my description didn't slide back toward my usual defaults. So I don't feel like that contributed to physicality in the same way.)
See, I think there is nothing wrong with that description at all
I thought of that after I posted it. Mind you, that's a phrasing that only works in some contexts -- which is likely to be true of any of the more evocative approaches, because not every perspective is going to work with a given metaphor or analytical distance or what-have-you. But if I were writing that scene, I know my instinctive approach would be more interior: if I'm in Sherlock's perspective, I'd be more likely to describe the emotional reaction he's controlling rather than its outward manifestation, and if I'm in the cabbie's perspective, the lip twitch might be in there, but as a side note in the cabbie's perception of the fact that he's managed to needle Sherlock (the lines around it are "you're just a man, but [Moriarty] is so much more"). "If he let it go further" is a judgment that might fit into the cabbie's pov, but not Sherlock's, and it feels most natural to say that when I'm speaking from a more exterior perspective.
I'm also coming around to the opinion that omniscient is vastly underrated and needs to be used more in modern fiction, but that's a separate discussion. :-)
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Not often, no, and when I do, it usually comes after the fact. Having a casting in mind from the start is rare.
. . . and now that I think about it, one other case where I know I had a casting from the beginning was Paul Bettany as Jack Ellin (In Ashes Lie). And I also feel like I have a better physical sense of Jack than I do of many other characters, so I may be on to something here.
(I also had Amr Waked cast as Suhail before I wrote him in Voyage of the Basilisk, but that came via a Google Image search, not via seeing Waked in a lot of roles. I wanted a good visual reference when I described Suhail because, quite frankly, Arabic men are not common in my daily life, and I wanted to be sure my description didn't slide back toward my usual defaults. So I don't feel like that contributed to physicality in the same way.)
See, I think there is nothing wrong with that description at all
I thought of that after I posted it. Mind you, that's a phrasing that only works in some contexts -- which is likely to be true of any of the more evocative approaches, because not every perspective is going to work with a given metaphor or analytical distance or what-have-you. But if I were writing that scene, I know my instinctive approach would be more interior: if I'm in Sherlock's perspective, I'd be more likely to describe the emotional reaction he's controlling rather than its outward manifestation, and if I'm in the cabbie's perspective, the lip twitch might be in there, but as a side note in the cabbie's perception of the fact that he's managed to needle Sherlock (the lines around it are "you're just a man, but [Moriarty] is so much more"). "If he let it go further" is a judgment that might fit into the cabbie's pov, but not Sherlock's, and it feels most natural to say that when I'm speaking from a more exterior perspective.
I'm also coming around to the opinion that omniscient is vastly underrated and needs to be used more in modern fiction, but that's a separate discussion. :-)