Er, you may have that confused with another CT Paul. The SCT006-000 that OEM is selling has no internal burden. It has a turns ratio of 800. So if it were used in place of a 2000 turns SCT013, the result would be 2.5x the actual value. That doesn’t include any additional error for different phase correction, but you would have to consult the experts for that.
It is supported with a simple menu click in IoTaWatt.
I’m no expert in modifying the emonpi firmware, but the new calibration should be 36.36 if you can figure out where and how to do it.