Suppose we have a portrait with two light sources.
....If you want more contrast you diminish light on the "darker" side etc...(
If all you want to do is establish a lighting ratio between the two sides of your subject (using lights), you don't need to mess with the meter: just move the light on the less lighted (darker) side further from the subject.
For example, twice as far away will give you a ratio of 1:4. Work it out from there.