Dash attaching screws - size/thread specs please

Just a point of interest:
You included a photo that is perfect, but let us know what year make and model you are working on. That really helps us even more help you.
Good luck in your challenge. Some of us have been there before. I found buying a rotted parts car is REALLY helpful in cases like yours. Sometimes just having another car complete- it could be dog snot but it’s all there is good for those little parts and pieces.
Syleng1