Seeing as I put the [seriesnamne seriesnumber] bookname in the Title in metadata, it seems that I am covered. I sort by Title, then I sort by Author, so I see everything listed nicely.
As for crossover, and sub-series, I don't think anythying could handle ir properly. If I ever come across such a situation then I will use something along the lines of [mainseries mainseriesnumber - subseries subseriesnumber] bookname in my Title.
So I won't bother with the series tag. I'll look up CC, see if it can help more.