You can pretty much use whatever you have available but if you want to save on some work on generating your own thermistor table and editing the firmware code, I recommend looking at the one you're using (Sprinter, Teacup or Five-D) and using one of the choices there.
On a related subject, where should be thermistor be placed using this heated print bed? The web page mentioned does not seem to mention a thermistor at all.
Yes. I think people have different opinions on where to mount the thermistor. I have mine taped in the middle of the PCB (circuit trace side). The PCB is mounted with the thermistor under the PCB and the aluminum build plate (around 3-4mm) above the PCB. In this arrangement I expect the thermistor reading to be higher than the bed surface and I've measured it to be around 10 C difference.
