Values settings should be done while there is -12V at blue trace and until value for that trace changes. Set bits for 1st value (top left caps) using first 2 switches and set 2nd value (top right caps) using another 2 switches. Result is ready when bit sequence represented by caps at top is the same as these at the buttom. It also handles overflaw like computers do. I've tested all 16 combinations and it works ok.
