I'd only use the recommended citric flush myself. no.
and I'd only use it if the parts determined to have corrosion and damage. and I'd be prepared to replace the radiator if I had to use it.
pull the block plug, and see what comes out. look into the radiator and see if the tubes are plugged or corroded.
then flush normally, and see if the gunk and corrosion is still present. only then would I use the citric acid flush on this car.
also pull and inspect the water pump. the vanes could have been corroded out.