No Greg, I don't have any other good recommendations. More droppers and shock at night in clear, low conductivity water. I haven't looked specifically at electrode configurations and electrical fields, but I've used "dropper bar" boats like yours before, and they worked just fine. Not sure if the Wisconin rings will make any difference, actually. I remembered a couple of good low conductivity stories. We were shocking the Colorado River in central Colorado using a generator and control unit on shore. Conductivity was low, and we had lots of volts but no amps. Our ground was a cable that we laid in the water near the generator. Well, it had a clip on the end, and I clipped it onto some car bodies on an outside bend of the river. That did the trick! All of a sudden, I could read some amperage. In smaller Colorado streams, we actually used the old trick of carrying a salt block (cattle supplement). When we hit a stream with extremely low conductivity, we would put the salt block in the riffle above, and that put enough ions in the water to let us shock successfully. Amazing, actually.
