The top kill seems to stand a better chance, because now that the flow has stopped, they should be able to pump mud down the choke line at the top of the well, and fill the well with mud.
Before when they tried this, the well was flowing, so as soon as any mud entered the top of the well it was just swept away.
I feared that the intercepting well would have the same problem if the well were still flowing. Any mud that entered the bottom of the well would be pushed out of the top of the well by the flowing oil before enough of a mud column could be built up to overcome the oil outflow pressure.
Plus, the bottom intercept well runs the same risk of simply becoming a second gusher. And if it does, there is no place for a second intercept well to intercept the original gusher well.
I vote for top kill!
I would think one advantage of top-kill first is that when they have to pump mud into the bottom kill, they won’t have to release the oil that is in the main well to allow mud to flow up, since it will be full of mud.