Workspaces can be reduced to a list on windows to show at a given time. Say you start on ws#0. When you "switch" to ws#2, you save the list of currently visible windows, hide them, then get the list of windows on ws#2 and display them.

This would be a good exercise to start digging into wmutils, and make your first script. Here follows an example implementation if needed (don't spoil yourself too quickly ;))

As for "gaps", you gotta do the maths when coding your own tilesets.