Its time consuming but it can be done. get one of your locks and a big pile of spare tumblers. Gradually build the lock up bit by bit, fit the key after each fitment of a tumbler. pop the key in and chack the tumbler is flush. Repeat till you get them, all in without any bits poking out. Once you get this far, strip it back down and lay the tumblers out in order, note the markings on each one (notches on the side of the tumbler) and write this down. This is your lock code, use this to build the other locks.
Other option is to remove the ign lock, and strip that down, note the codes as above. You need to drill a hole in the right spot to pop the lock out, then apparently you can bash a pin out of the ign lock to strip it down. I havent tried this yet but according to the vortex it is doable!
As a last resort if you cant get a tumbler that fits in a particular slot, you can grind it down till flush. However if you do this there is a chance the lock will end up working with more than one VW key!