If you want the portraits to have a similar "look" or "style" as the rest of your project, you could use the 24mm for full body portraits and the 85mm for everything else. There's not one magic focal length for portraits, but can be dependent on your style. I've seen phenomenal portraits with 20mm lenses through 300mm lenses, but those obviously had different feels to them. I personally really like the 50mm focal length as I can take a few steps back and get nice full-body portraits, or take a few steps closer and get some nice headshots.