Thought I might have to do that. Maybe I can put my AnyVolt with 20 turn put into good use!!The empirical method may be your best bet.
You could take a variable power supply and a series resistor and hook up the meter all in series. Then starting with the power supply set to zero you could increase the voltage very slowly until the meter was at full scale and then do a bit of calculating to confirm the value of the current.
hgmjr