If vibration is so bad on a .40 size airplane that the motor or radio equipment is being damaged, you can bet the prop is not the cause. Unless the hole was not drilled in the center of the prop, you've got other problems.

The difference between a balanced prop and a non-balanced prop is very small if the engine is mounted properly on a properly built airframe.

I've probably had 30 engines and almost as many airplanes...I sold my balancer after the first few. That doesn't mean it's right, but my personal opinion is that it's not worth it.

Just about everyone I fly with goes striaght from the hobby shop prop box to their airplane without balancing...It's a PITA getting them balanced anyway I hated it. I think I would rather sand a LE and hinge the ailerons!

Of course, this is only MY opinion.