Is there anyone using the Zone VI twin tube cold light head with the two dials that read A,B,C... and the main brightness setting dial? I have just started to use one of these and am looking for either some first hand advice on what settings to use for different grades, or a copy of the manual - if that was covered by Zone VI. I plan on running the standard tests with a step wedge, but would appreciate some ideas on starting points, or successful settings.