I haven't personally done this in ETABS. But, when I've designed structures like this before, my process was the following:
i) Steel Decking was based almost completely on span tables from the decking manufacturer based on the weight of concrete and thickness of the slab.
ii) I don't think I've ever designed a concrete slab (spanning between steel beams) that was poured into an un-shored steel, non-composite decking. The deck had to be sufficient to carry that load without any help from the wet concrete. Therefore, I would think that merely adding temp / shrinkage steel to the topping slab would be sufficient.
Maybe someone else can comment. But, I don't really see a calculation that needs to be done.