Thinking about the whole slide bar / motion plate problem led me to looking through my archive where I found a works drawing of a later period, which showed half the motion plate and using the magic of Photoshop I again copied, flipped and joined the images to give me a complete motion plate. It may be a pig to cut out of brass so I might make a pattern and cast them in whitemetal instead.

'course the slidebars are something else again...........................