@MeltemiCaz that data logger looks good but may not have the sensitivity to see any leakage currents. I couldn’t find its lowest level sensitivity but if but active and neutral passed through the sensing core you could hopefully see the imbalance ( leakage).
Anyway, I am keen to hear your report about your trip margin when the B-Stop is installed. If you want to simply do that installation quickly to try it, wire it to a three pin plug and put in to one of your GPOs. You will see the change with the leakage current meter immediately.