I've fitted a new bezel by crimping, the result is not as bad as everyone seems to be making out.
Remember that its only the very edge of the part that's turned under that's visible, the rest is hidden by the clock holder.
I clamped the clock/bezel/seals down to a piece of wood with a soft jawed quickclamp and used a pair of slip jaw pliers with a piece of scrap aluminium to protect the bezel and just worked around the bezel gradually crimping it further over with each circuit. As long as you don't try crimping over too much in one go, do it gradually and the results are pretty good.
The only problem I had was that I couldn't use all the seals supplied, there wasn't any bezel left to crimp over with all fitted, so one of the flat ones had to be left out and the back sealed with silicone.
Once on the bike you can't tell the difference between the one I rebuilt and the other that was professionally rebuilt some time ago.