I've heard from John Preston that he used to spin coat very large sheets (perhaps vacuumed down acetate?). The sheets were about 30x40". They were coated with a silver halide gelatin photo emulsion and used for map making somehow. He says they got good even coatings, so I guess it can be done even on a very large scale.
My guess is that this technique is best for very thin coatings, and figured it probably wouldn't work for very thick matrix film coatings.
Regards - Jim Browning
Again, it is no big deal to multicoat. And if there were reason to get fancy: some of these coaters have multiple injectors, are fully programmable, so you can push a button and go away. It'd be no big deal to have a plate wetted, spun, aired, baked, wetted, spun etc. ad nauseum. The nice thing about the process is that it is quite scalable, I'd see no problem getting up to full plate size at low speed (couple hundred rpm).
But the proof is, of course, in the pudding. So let's just see!