You need a phase wheel, V blocks or a lathe and preferably a DTI.I think it's the cam lobes, which are possibly a shrink fit on to the shaft and could have spun out of position. I'm not sure how you might go about measuring that? Especially if you don't know which lobes have or haven't moved.
That said without a known good camshaft to compare with or the VW cam data it might involve some guesswork.