Holley stumble trouble

I believe your issue is a combo of to lean on idle/transition and slightly delayed primary coming in at light throttle.
^^^^This is what I’ve suspected the whole time. Question is, how to correct it? I’m not sure I’m interested in trying to drill out these tiny holes or press in new ones. Perhaps a replacement adjustable metering block is in order here. I briefly considered a ProForm main body but they do not come with blocks and there is no provision for a vacuum advance port if using my existing block.
I agree the IAB in particular seems very small. Maybe that's the secondary block??
Negative. It’s the primary. I’m gonna measure again to be sure but I was pretty careful the first time around.