Arranging subgraphs and positions of elements in a digraph

What tactics can be used to arrange the dimensions of a subgraph in a digraph diagram? It appears that edges between nodes can only be constrained by a minlen constraint and not a max length constraint. I have tried adding invisible nodes and edges to the diagram to fix some of the spacing and alignment issues for edges becoming too long and try to to condense them a bit. This has only resulted in the entire diagram becoming larger and the spacing/alignment issues not being solved. Are there any other tactics that could help out solving these alignment issues?

I’m not sure graphviz ls well-suited to what you are trying to do.

You might want to look into Tim Dwyer’s WebCola, which handles a more general set of layout constraints.