The handle for the Y crank on my X3 keeps vibrating to the bottom of rotation because it doesn't have a balance weight on the other side. Guess that means I must mutilate the machine some more and drill and tap a hole for a counterweight bolt?

No, this means you need to use your gib locks. If you really want it balanced (which wont fix a movement problem) use stick on auto wheel weights on the back side of the handle. No need for mutilation.