Mike,

there's nothing wrong with canting the rifle. So long as the angle of cant is consistent, it's a simple way of briging the sightline nearer your eye. However if you can put a new bit of wood on the cheekpiece assembly, this will be easier.

Odd that the rifle is a KKM, as the KK200 was introduced in '96-ish. Does your Walther have a round or square receiver?