Yes the Minimal Grid is different than Grid as per Preview in that the resulting model for Minimal Grid only contains the boundary of the encompassing models but Minimal Grid still uses the grid size in the box. So think of it as the sampling resolution for the models in the group. I reduced it to 100 and I saw a few of my pixel disappear because they must have lumped in with nearby pixels due to sampling.
Anyways I would hold off if you can on sequencing with model groups. Dan has some wonderful changes in store for us. He let us checkout some preliminary code and its awesome. I don't want to spoil too much of the surprise but it will reduce the number of models you need to work with because you will be able to change how an effect distributes onto the pixels on a per effect basis right on the grid. So no more of what I call proxy models.
