That page looks rather dated. Yes, I think your idea is correct but it also depends what crowd you’re referring to. Ideally, all Whonix users would have the same screen resolution. May not matter what other Debian users do, since Whonix doesn’t hide itself.
I would argue that using Full-Screen is important for behavioral reasons - so you don’t shoot yourself in the foot by accidentally confusing Host & VM windows. For example, using Qubes, it’s possible for me to have multiple windows open from multiple Workstation VMs. Even though the windows are color-coded, it’s easy to type accidentally in the wrong window. I actually take it one step further and use a separate virtual desktop for each vm: host / dom0 / gateway + workstation1 + workstationX…
Hard to say. HD (1080p) has taken the top spot in the US according to your links. Maybe most Whonix users are in underdeveloped countries or maybe they’re all techies with 4k monitors…
Building a usable anonymity set would require sticky defaults - including Host OS packages to enforce or warn against resolution changes. Tor Browser addresses screen size fingerprinting. Are there other programs that you’re concerned about leaking screen info?
with guest additions installed in whonix workstation, setting the workstation vm to “full screen” will integrate the vm with the resolution for your host os. however, in the “view” menu, there is a “virtual screen x” submenu that offers a number of different resolutions to set for a vm. this will run it in windowed mode at the chosen resolution. i have not really experimented with this or run any tests to see what may leak if properly exploited. but, the functionality appears to be there.
with that said, i’m not sure if this is a security issue vs. a usability issue. are there any exploits we are aware of that break out of a window in order to determine the desktop size? would this be a use case that malware developers would concern themselves with?
The resolution differences are not enough to damage your anonymity. Usually not detectable if you follow TBB best practices (also they are working on fixing it so you can maximize without detectable remote differences). As for a locally present adversary, you will have a lot more problems to worry about than them detecting you have a different resolution.