Torque converter fluid?

[Mt Man Chad]

I am getting close to putting the motor in my truck, and was going to drain the transmission fluid out of the torque converter.

I replaced the filter and gasket in the transmission the fluid was clean that came out. I'm closing in on starting the engine and running the trans that has been sitting for 12 years.

What is the trick to changing all the fluid out of the converter and filling before startup and how much should I put in....