Don't worry, I can understand you. You are not suffering from aphasia
You can edit the default window tint of a vehicle by editing the hex value in the '<diffuseTint value=' line in a vehicle's 'vehicles.meta':
Example:<diffuseTint value="0xAA0A0A0A" />
I'm not sure of the exact values myself but this looks promising & might be a good place to start.
Use Notepad++'s (<scroll down for x64 if required) 'Replace' (Ctrl+H) functionality to allow you to do it a lot quicker for multiple vehicles.