TS-SS and Cosine similarity among text documents using TF-IDF in Python
Normalised vectors have magnitude 1, so it doesn't matter if you explicitly divide by the magnitudes or not. It's mathematically equivalent either way. 

I see no reason that you couldn't use normalised vectors in TS-SS, but it seems that the main motivation for using TS-SS in the first place is that it makes more sense for vectors that may have different magnitudes. I would try both cosine similarity and TS-SS for your problem, and see if there is a noticeable performance difference.