I only did that much over balance when the RPM was 8500 or more. Even a 1% over balance is a bunch.
You also have to remember when you over balance like that you can end up with a low speed out of balance issue that may be in an RPM range that the engine can shake itself to death if you stay in that RPM.
An example is a 500CC two stroke. They are as much as 50% over balance IIRC (been awhile since I've done one) and they SHOULD shake a bit at idle. If they don't...it's a short life for them.
