My VKM4 was purchased without mist hardware. Two years ago I added a KoolMist unit ($115). The mist was manually turned on/off with the air needle valve. The mixture set at the tip. It was a pain keeping the mist air/fluid ratio correct. The 8200 control (and 7200) has a front panel MIST COOLANT button and M7/M9 available. Someone on another forum found a mister with a two needle valves (($25). It also has a check valve in the fluid line to stop draining the fluid back into the reservoir. I located the mist control terminals on the schematic and in the cabinet. Added a rail mounted relay to control an external air valve. Put a Harbor Freight air regulator in line.
Works great!
I also added a 24000rpm auxiliary spindle...but that's another story.
Ken