Before I did anything with the holes, I'd verify where the blades are relative to the transition slots. You only want .030-.040 showing. With that cam, I've never been able to not have holes in the butterflies.
That's why most of the new carbs have a built in, adjustable air bleed system. It presents a controlled air leak so you can get your idle speed up and the throttle closed like it should be.
But there is nothing wrong with the hole. I think you still need them.
