Your cam doesn't need that much initial advance, it's hardly bigger than a stock 360 4-bbl cam so I'd back it down to about 12-16 btdc and reset the idle speed. Your throttle plates are likely closed too much at idle the way it currently is.
You say in the OP it's rich during cruise and lean during power, what AFR numbers are you actually seeing? I've noticed with mine there's a lot of overlap between the idle and cruise circuits, more than "traditional" carbs and I think they intended it that way.