Gear cluster shim -what size?

[Egee]

I'm re-building my TV200 gearbox and noticed that the shim between the base of the gear cluster and needle roller bearing, had become oval in the centre. I ordered another one. When it came it was labelled for Spanish models and measured 1mm in thickness. Compared with the original which was 1.4mm. Does anyone know what is the correct thickness, and where I could source one?
Many thanks