Hmm, these are not colloids that I am spinning, so yes, there could be some radial intrigue. On the other hand, if the solution is sufficiently viscous then the Stokes force should keep things more or less together.
I could also mount the glass off center so that the material sweeps across it more like a rainbow curve.
It'll just have to be tried.
Suggestions as to which emulsion to use?
Perhaps some lampblack wc paint in 10% gelatin could be used for rough tests - it would give a visual indication of coating uniformity, and be a tad cheaper than using silver.