Per Gochermann’s emails, the thermistor details are: “The thermistors are simple PT100 sensors ("Pt100, IEC60751, F 0.15"). We attach them directly to the solar cell, and add leads inside the module to create soldering points on the module rear side after encapsulation. You simply have to solder 2 thin wires to the soldering points and connect them to your circuitry. They’re 50 EUR each. We can put them to any solar cell of your choice.”
We are putting them on modules 2, 8, 12, 16 to get a good distribution of the temperature across the cells. The blue 'T’s in the PDF below indicate the placement.