The 4l60e torque converter itself should hold between 1 or 2 quarts of transmission fluid.
Just add a quart of transmission fluid to the torque converter and then put the torque converter onto the transmission and then after you get the engine back in place you can add the rest of the transmission fluid to the transmission.
Then start the engine and let the engine idle while slowly pouring more transmission fluid into the transmission.
The transmission along with the torque converter should hold between 12 to 13 quarts of transmission fluid but just don't overfill the transmission.
Add a little at a time after adding 4 quarts until the transmission is filled to full.