Did you look online for the manual or videos regarding the DOD Looking Glass Overdrive? Robert is usually faithful to the original design, so that would be the first place I'd look. With a quick search, it seems like DIP 1 changes the input impedance slightly - but I didn't continue searching for what DIP 2 does. If you can't find any more info, then review the schematic (apologies, I'm not familiar with that pedal). Good luck!