I usually hump in 2 throttle with about 30-40 lbs of independent set. I added a 3rd SD40 to the hump set for the extra braking because of this. The train pulls you over the hump until about the last 20-25 cars. 2.7 has been the speed that works reliably for me, although anything from about 2.3 should also work.
I've also found that with WC's hump, I need to stay in draw distance of the bowl. Flying further away causes strange anomalies in car routing, tracks self-deleting, and occasional corruption. You can check to see how the bowl is filling, look at the receiving tracks, or open tagger to look at the cut you're shoving, but not much more than that without rolling the dice.
Another oddity, and this may be with Barstow as well, is that when the last cars are rolling down the hill, I can't immediately relinquish the hump power to AI, or the last few cars may be misrouted. I wait until the last cut has made it to its track before initiating the AI Recrew.