Dummy 13 needed it's own phone to take selfies of it's poses.
You'll want to use Tree supports for the hand. Clean them out and a very light brush with a file might be needed. Then the phone should slide right into place.
All print testing done at 200% but it should work at 100% as well. Let me know if it doesn't fit.
Maybe I can make one where it holds the phone for taking photos of others, or a selfie stick. Let me know if you want it.
The author remixed this model.
Reposed one of the hands to hold a phone.
Scaled down the phone to approximate scale to fit the hand \ dummy.