Stupid question alert sorry

3 sizes.

25.4mm - 26mm - 31.8mm (oversize)

the coke can/beer can shim trick would be fine going from 25.4 to 26 - but if you are going to shim a 26 out to 31.8 you might be better off just buying a proper shim (chain-reaction is a good source).

You could also just get a new 26mm stem to use with the polished bars.

missed out 22.2