At "wildbillbugman" Bill's suggestion, I am hereby mentioning that I have access to a spincoater that can handle plates up to 6" diam. I spincoat quartz and silicon wafers with photo- and e-beam resist as a routine part of my research work. I believe that the technique may work well for film emulsions and should result in very high uniformity except at the very edges. I am happy to try it out and will do so as soon as I find the time.
Has anybody else here tried spincoating?