All the dig sites are the same (within a very slight margin of error) in terms of expected value. I don’t think it makes sense to stop collecting AP unless you are already above 134k and ready to super ascend.
[Raises hand]
You should choose dig sites based entirely around when they will finish regardless of how “advanced” of a player you are. You should be optimizing for a completion time that:
(a) is not when you are asleep
(b) is not shortly after level completion
True ... but ... I also optimize based on impact of 8 hrs Insane TW with +50% Faster Digs, which makes it wasteful to use on 100% Common which takes on 3h15m, so 4h45m wasted, compared to 7% Rare 10 hrs = 2 hrs after TW, which makes the Rare & Epic digs worth more than previously b/c they can be finished much quicker, and the Common digs less valuable b/c they would waste TW time.