The concept of observer moment is not clear. For example, you could compare each observer moment to the node of a graph and the transitions from one observer moment to the links of the graph. However, it is well known that a graph can be transformed by changing each node into a polygon. Each link then becomes a node. In this new format, you could view "Time" as being represented by the nodes. We are left with two representations of consciousness: the first is a feeling of becoming (the first representation in which the links represent time) and the second is a feeling of being (the second representation in which the nodes represent time).
Ultimately observer-moments are the stuff that makes up the plenitude. They are more fundamental than any physical object and more basic than time and space. If we are to assume some fundamental entity, I think that observer-moments qualify.