Lengthening Thermistor Leads with Different Gauge Wire
Extending the leads with almost the same wire gauge would be fine. That part number offers only a 10K or 30K (at room temperature, or 25 deg C) option. The wires resistance is too small to be a factor here, unless it has to run several feet or more. Even then the main issue would be noise pickup, so you would need to use shielded cable and RCL filters before you send the signal to an op-amp for amplification and scaling. These thermistors do not respond to temperature changes quickly, so a low-pass filter of 10HZ would be fine.