Each user would have a front end installed on their own computer. The
articles in the links I provided in the previous posting in this thread
contain more information on that subject.
Consider a web browser, which is a portal to the internet, not the internet
itself. A front end is a portal to the data stored on the back end. In
some business situations users need limited internet access, maybe to just a
few sites. A web browser can be configured to allow users to go to those
sites and no others, and locked to prevent the users from making changes to
the permissions. There is in effect a customized "front end" for the
internet. From the user's point of view all that is needed is to open the
available browser.
Users don't choose the front end. They open the only one available on their
machines. Different front ends can be provided for any number of reasons,
from providing a different set of forms and so forth to providing a
different physical appearance. The main point here is that the user has
only one option.
The utility I used does somehow "sense" the screen resolution, but I don't
know how.