Undoubtedly late to your need, but in case anyone else comes along, Aria can be quite hard to satisfy on this issue especially in late game.

It helps to realize she only actually cares about how far souls have to walk for their next reward. If a soul needs a certain color, but has to walk past a tile because it is full, then that makes the walk longer even if the road structure is fine. Thus having a good variety of rewards in every section of heaven is important and even more important is not letting them get too full.

The opposite is true in hell. Jasper will be satisfied as long as souls have a long walk. You can actually have a pretty efficient road grid as long as you group colors together so that souls have to walk a long way to find the next one.