Turn the cameras upside down, or flip the video? Or if possible extend the needle below the pivot point and add weight so the gauge operates the correct way up.
Turn the camera, so simple I never thought of that : )
The IP Camera Viewer 4 is a free program, which even has an option to do that.
It is a very stable program I would add.
The other way you mentioned looks a bit more involved.
Extra weight as you say to the pointer is required, that is without making it look silly.
Thinking about it the meter is probably large enough, may be the camera would focus closer to make the image larger.
I had to glue an old spectacle lens in front to sharpen it at its present distance.
Other cameras I have tried with manual focal, will not run at high enough resolution over the USB cat 5 LINK.
I have tried USB repeaters in the past to try and get round this, but they were problematic.
The cameras I use are Microsoft Webcam 2000's