I used the following settings to get a good exposure on the Huisun 10X for license plate viewing at about 100ft. to 125ft. IR on.
I only cropped the images to remove dead unused area to reduce size of file only.
Images taken between 12:30am and 1:30am in very low lighted area of the street. Residential.
Test images with an extra license plate placed in the position your focusing on.
1. PTZ to the location desired.
2. Set the Image / Exposure settings to Shutter Priority, Shutter 1/1000, Exposure Bias On: Comp Level 50, Cain Limit 50
3. Image / Focus to Manual, Min Focus Distance to INFINITE
4. Manual focus the camera to the the general distance of where license plates will be.