5.9 Magnum flywheel - DIY with bolt-on weight??

http://www.moparchat.com/forums/showthread.php?t=71263

Everything I know about this is in the above thread including a diagram of where the weights go in post #12.

Note the experience of 340Duster1 racing his 5.9 with flywheel balanced substantially different than what I came up with. Perhaps the engines survive without accurate balancing I don't know.

How are you deciding if your engine is balanced?