If your going for the shimming with sheet metal coke cans cut up are used alot for shimming handle bars/seatposts so I guess cut correctly they might be ok, since I'm scottish I find that you do get better results from Irn Bru cans though. Not sure if I really like the ideal of shimming a headset though it will make it very hard to install straight and getting the shim in correct all the way round.
If your going for the shimming with sheet metal coke cans cut up are used alot for shimming handle bars/seatposts so I guess cut correctly they might be ok, since I'm scottish I find that you do get better results from Irn Bru cans though. Not sure if I really like the ideal of shimming a headset though it will make it very hard to install straight and getting the shim in correct all the way round.