Fog needs time to build, these formulas can have dmax to 3.0 or more in less than 2 minutes.
Lithing with film usually is done with a high contrast film, athough conventional films have such a high gamma with this stuff you might not know the difference.
Exposure is a subjective thing. When I shoot lith film it in the camera I always bracket at least two half stops under and over. You never really can pre visualize the effect of where the white to black cut will occur when the high gamma slope will translate some 'shades of grey' things as clear, and others slightly lighter as black.
Shooting slide dupes with lith film and develoepr can also be an interesting way to see how the scene can be abstracted in a different way, since some of the original scene range has been compressed already in the transparency.
There is a mid 80's or maybe late 70's HP Photo book called 'High Contrast' by Elinor Steckler (I think that is the authors name) that gives all sorts of good lith film examples to fire your creative juices.