Is it larger than 1920x1080? DU4 is optimized up to that resolution, but for resolutions larger than that I may have a solution which narrows the width of the page in comparison to the viewport.

Aside from that, customizable font sizes is potentially possible. To clarify, you're on a large monitor, but you want the font sizes smaller so that more text fits on the screen at once, is that right? If this is a big issue I may be able to whip up a "compact" view, although that might take a little time to produce.

In the meantime, you can always switch to "Skinner Mode" if you prefer the old look of DU. It's basically DU4 with a reverse-engineered DU3 skin on top of it. You can change to Skinner Mode by going to My Stuff > Account Settings, then scroll down to the Visual Appearance area.

By having a zoom option, we can scale up or down the image in a window automatically without affecting other windows in same browser instance.

I was switching back and forth by just adding or removing the du4 subdomain. When doing that, I could see the instant differences.

a way to increase the size to what it was? Potential for larger font option? It’s difficult for me to read now due to older eyes

I read on an iPad and have to pinch out now constantly with new version whereas older one is totally comfortable.

I’m going to have to look into this further.