I think we really need to get rid of this mentality on a "logical" training board. Really, do you think you have the capability to get Lee Priest's arms? He's a genetic superfreak, with a genetic disposition to grow even larger arms than his superfreakiness would allow. Plus he does huge amounts of gear. Why would you even give a shit about what he does for arms?
You can grow big arms by not doing ANY isolation movements. Biceps are worked hard in close grip chins, and rowing movements. Triceps are worked in the dip/bench.