The browser at regular old 100%.
Here, I've set the zoom to 50%, shrinking everything down.
A pretty low-profile feature of VFX is the ability to save an image of your application to your computer: the "Snapshot" tool. Maybe you want it for a PowerPoint or for your ...blog... or whatever. An evil trick you can play on the snapshot tool is to change the "zoom" of your browser, then take the snapshot. Since the snapshot image is created by VFX within the browser, when you set your browser's zoom to 25% (making everything tiny and allowing for more content to show) VFX thinks you have ginormous monitors and will generate an insanely detailed poster-sized image.
At 100% browser zoom. Resulting snapshot image dimensions are 1916 x 995.
At 50% browser zoom. Resulting snapshot image dimensions are 3832 x 2073.
At 25% browser zoom. Resulting snapshot image dimensions are 7664 x 4229.
This is the method we used to create the massive shipping traffic maps a few weeks back, and I hope VFX users out there give it a try.
P.S. Your VFX instance has to be within a web page that grows or shrinks to fit your browser. If your app is embedded in defined dimensions, you'll just get a regular screenshot with a huge background (like our homepage up there).