[Amps] calibrate meter

[bubba willis]

ok i have a 0-10 volt dc panel meter with an internal resistance of 10.00
k.ohm
it is on this site
http://www.gmetechnology.com/products/groupB/meter_analog.htm   product
number PM89-D10V  can anyone help me with parts would be necessary to use it
for measuring a 1.8 amp 4000 volt dc power supply on my amplifier. i would
like to use a trim pot to be able to calibrate it to my Simpson 260.

i also have the PM89-D5A with an internal resistance of 8.3 ohms that i
would like to use to measure my grid current and have it full scale 500
mili.

thanks for any help that anyone can give or even a link to a good step by
step i have looked around and not been able to find anything