let me clear up some mis-conceptions......
you do not fit the pistons etc to the crank to balance them as a lot. On certain crank designs dummy weights are added to simulate a rod
each part is balanced individually . there is no point statically balance anything that rotates, you must spin it, eg crank , flywheel, clutch and front balanacer/pulley
normal engine rebuilding processes rarely change balance to any significant amount, as they remove so little metal.
rods are static balanced both end-to-end and whole. the hard part of doing this at home is making a jig to hold them in EXACTLY the same way every time you sit one end on the scales. franctional errors in hanging the rod, will give errors of a few grammes, so you are wasting your time.
most sets of toyota rods are balanced to within about 4 grammes (prettly ordinary), however there are big variations in weights of the forgings between different engines of the same model. there is no sign on most 4AG rods (for example), they were ever end-for-end balanced, one end only.
most modern engines are reasonably well balanced so there is little to gain, however we still see some engines very poorly balanced. the worst Toyota parts are flywheels and clutches.
most of our perforamce engine rebuilds involve some level of balancing
