So, just had a word with my mate who makes the domed centres for wheels and he assures me that they will fit over an already domed surface no problem, so regardless of the shape under the existing one, it's a go-er I think!
Just need to wait for the new style RS knob to be delivered from Rofag and then I'll crack on. (They DO fit on a 197 right???!!!)
In other news, he can also do them oval shaped so they could be made to fit the standard gear knob too.
Once I've played guinea pig, we should be able to sort these out for anyone that wants them.
RS Aluminium knobs merely come in 5 or 6 speed designation (As both 197 and 200 6 speed gearboxes need the collar lifted to get reverse).
So in answer to your question. Yes it will fit.
Which is always a good start..........