Just re-keyed the lock on a recently bought (secondhand) Wunderlich toolbox. What a bloody faff!! Big fingers and tiny components, poor eyesight and lighting.
After a couple of hours of dicking around, I finally got it, wafers in, springs in, barrel reinserted and bingo, all done. Only had 4 out of the 6 wafers available but it's only a tool box.
I would recommend using a bit of masking tape on the wafers, as you find the right one. Stick it down and then repeat for the next wafer. The springs are as small as a bee's antenna! If you have a jewellers loupe or similar, that would be handy.
Next up is re do the barrel of one of the pannier clamp locks that fix the box to the bike. The dealer where I bought the bike, kindly did all the locks for me but this one is very fiddly to get unlocked/locked. All the others are ok.