By AGX's input, presuming no suitable answer come in on this thread, I figure 1 will be the battery test pot, one will be high, and one will be low. And I'll just have to tinker till I get which is which. To answer Paul, I don't remember how far off as I'm not working on it this minute. But I do remember that last time I fooled with it I was afreaid the CdS cell might have lost too much linearity and thus borderline bad or actually bad. But at that time I didn't have APUG at my (gracious) disposal.