Something else that comes to mind regarding the film coating machine: that it should be possible to scale this concept down to coat 35mm film base...providing a source is available. You could (potentially) use 35mm film projector sprockets and rollers for film transport.
Just a thought.
Since coated width must be narrower than the support for technical reasons, and the edges are defective, this method would either be extremely messy causing loads of defects, or produce a product that is underwidth.
It is better to coat wider and cut down. This has been the experience of ALL manufacturers to date.