I took a better picture of the panel for this yesterday http://bitsavers.org/pdf/dlcCompany/cowculator
Other than a couple of want-ads from the early 60's I've not been able to turn up any more information on this. I'm assuming you optimize by adjusting the parameters to zero on the meter. Other than what is on the panel, I've not found anything on the DLC Company in Linthicum, Md.