Very interesting thread. I'm with Sylyavski on this one and I don't think shrinking is that much. Considering the viscosity of the epoxy, pouring a few thin layers is not going to improve things much and I believe your'e better off with one thick layer. As an extreme example start with an uneven surface and try to paint layers it until its perfectly flat... But please carry on testing as its the one way we'll really know. Its difficult to test though as there are so many factors for example some epoxy likes to be cured cured at higher temps e.g. 60 or 80 deg Celsius so temperature might also have a big effect on the actual results.