Just before sundown suggests amber skylight, so ctb isnt needed. I would shoot anything facing the windows at actual magic hour to motivate diffused tungsten sources on the talent from the direction of the window.
Also, the dialogue and the purpose of the scene are necessary to understand the motivation of the lighting and composition of the scene, ney, entire film. "Looks cool" is not a reason, though "and it looks cool" is icing on the cake of a well-motivated scene.
Also also, if the audience can tell it's lit or they're distracted out of the scene from too much showiness and production value, then you haven't done a good job. lol
But, seriously, those bright windows won't be a problem anymore for a dusk shoot as those little Lowels will so a nice job of painting up the place and suggesting depth and dusky sunlight. I have some ideas how to shoot the scene, but I'm not DP'ing it and haven't discussed anything with the director, nor have I shot any other portion of the movie to make sure this scene fits well or feels right with the rest of it. So, bearing that disclaimer in mind...
Suggesting bounced dusk sunlight in a dark, dusty room with two characters stopping at a door and exchanging dialogue (i'm assuming they are on either side of the door facing each other, both with a shoulder facing the door), I would probably set up the two omnis on spotted at beadboard or foamcore that bounces a nice fill toward the door which should light the talent well for any OTS dialogue shots. If you wanna be tricky, have the Pro on that roof above the little office area to give one character a hairlight with a bit of diffusion so it's not so obvious. Then I'd bounce a Tota into another reflector (again, beadboard or foamcore) straight at the nose of whoever gets the OTS CU, about a 1:3 ratio against the key (the two omnis) to provide a bit of fill and a catchlight; repeat for the other talent's OTS CU. For the bg I'd use the DP's to make little pools or streaks of light tomadd texture to the background and provide separation from the talent. I'm also assuming you can juice all these lights at once. For dusk, you dont need to gell tungsten. Anyway, that's what I'd do given I haven't discussed the visual language of the movie with the director, attended any meetings or observed any rehearsals. I don't mind drawing diagrams if it comes tomthat or if you think it'd help.