Ive just moved over to M-PC and have set this up for control of my hazer.
As suggested above you can use presets - but i think a better way is:
Make a Hazer cue (using presets as well - that depends on what you want to do)
Hazer [fog: 100%, fan: 100%]
Make 2 "INHIBITIVE" cues. One for haze level the other for the fan set the levels to 100%, When you record them you can also put them in the playback banks and get faders for these.
Edit the override cues and set the startup fader level to 0%.
When you want to use the hazer simply fire the Hazer cue as normal - I do this from the playback buttons and just do GO. The inhibitive faders being started at 0%/0% will override the hazer cue from doing fog 100%/100% fan. The faders can then be used to directly control the % levels of the fog and fan. Need an extra burst of haze? No problems Hit the "Flash " button and hold it down for as long as you need the extra burst - the level will temporarily go to 100%.
You can additionally set the "Flash timings" so hitting flash gives you an 0-10 sec boost (well if use also use attack and decay it sort of gives you a 30sec boost...ish) to the specific setting.
Open up the cuelist options and set your desired hold time under "Flash timings". Then on "Function Assignments" set the particular flash button to be timed by toggling "Timed" to "Yes" on the right hand side of the window.
Alas the light does not stay lit to show the flash is still active during the timing but goes off when you release the button.
Alternative without faders but WITH variable level control:
Although not as convenient as the above method this doesnt take up faders (there are a huge number of banks so really taking up faders shouldnt be an issue - but in case you dont want too...). Use two separate cues, one just fan level, one just fog level set both to 100% - the actual level will be controlled by the cue's own intensity control during playback. Assign to the playback buttons. Fire pressing go (you need to fire both). You can then control the levels using the cure playback level found by using "actions" on the cue rather than "go". You can also use this to set the levels before pressing Go (which is also on the actions for convenience).