[Amps] measurement of Screen grid current

[Allan Greening]

Has anyone used a AC  photo-optocupler like PC8144 to measure both forward
and reverse curent flow in a "Tetrode" (4CX1000A) ..screen grid supply??
say p/o coupler across a 1 ohm/6w resistor in the Sg line es the p/o
feeding a LED bar readout.. yes i know u wont know if its + or - current
flow but so wot as long as their is min current flow at  tx'n!! de vk3pa