Need help with vibration!!

Well it's "simple."

If it does not vibrate in gear, then it's right there in the engine.

Determine if having the clutch engaged or not makes a difference, you might have torn up the clutch disc (tore lining off one side)

If it shakes while moving, it's something in the drivetrain, yet to be determined.

I've never heard of "balancing the back half" of a crank. Personally, this sounds like BS to me