It is great that you are trying to estimate the returns from the upcoming auctions, but using such a simple model is likely to lead you astray since GEM and MUS are quite different.
I suggest you start with any of the really detailed threads started by
@wombat777 over the last couple of months. He has put in hundreds of hours into his research and has generously shared it with all of us. A couple of hours reading his posts will pay enormous dividends for your understanding of MUS.