"Very large" is relative. Neo4j can handle large complex graphs, and the data model should support your use case, which means you have to know what questions should be answered by your graph. In general large number of relationships shouldn't be a problem, but if you have super nodes with massive number of relationships that can be a problem when you try to do traversals.
You can check this discussion and the stackoverflow link there:
About your "data model":
I don't recommend to use this type of data model. One relationship implies the other.
You can see good examples of this in this blog post: