Those pics for lightmaps scale areby using the command
mat_luxels 1
(they show you the blu grid, the scale of lightmaps.
Mat_wireframe 1
Shows everything that your computer is loading to the processor. So it even shows backside faces that aren't rendered, but they are in cue to be rendered (because they are in a visible leaf.
Best to look for performance issues.
mat_wireframe 2
Shows only the wires directly in view of player. Hides frontside faces that ARE being rendered. Allows you to easily see exactly what you're looking at only. Anything behind is culled (though still rendered).
Gives the worst idea of performance but easiet to look at for local wireframes.
mat_wireframe 3
Only shows the wires that are visible to player (anything in visible leafs), the stuff that IS being rendered. It hides unrendered but cued stuff. Easier to look at the wires, but doesn't give as good an idea of what is being sent to process.
(no backside faces)