John,
I think it's great that you are meeting with the factory rep. Density consistency has always been the biggest problem that I've noticed. Two different workers should be able to agree about the density of a piece within no more than 5%, allowing for a slight margin of error. That should be a much easier task than the much harder process of making the piece (which they already do so well). Another thing that would be great to discuss would be the various types of ventilation that they do (freestyle, flatback,...). Do they understand what we mean when we say one of these words? Sometimes I am not too sure they do, possibly because of language barriers. There is also the issue of consistency of wave pattern. Maybe pictures could be used to help communicate these different aspects.