Is there a way to increase the font in the PF3 Web Display window.
I'm not sure; I don't set the actual font size, I only define the ratio of sizes between the various elements (as percentages).
How are you actually showing Web Display in your VR headset? Are you using a standard web browser, or the MSFS in-game display?
[Update] I've had a quick play and I can see how I might be able to address this, but it will require a significant rework of the Web Display template.
I do need to know how you access Web Display so that I can verify that it works correctly (MSFS in-game display can be particularly tricky).
Cheers,
Martin