This exec says the sedan to Touring ratio will be 1/1.
https://autos.yahoo.com/m5-touring-o...165200685.html
M5 Touring Orders Are Greatly Exceeding Expectations, BMW M Exec Says
BMW M vice president of customer, brand and sales Sylvia Neubauer claims that current production of the latest M5 is actually split evenly between sedan and wagon variants. She notes that BMW has increased production for both sedan and wagon variants, but heavier interest has led the brand to increase production more on the Touring side; after initially planning to build the cars at a 2-to-1 sedan-to-wagon ratio, about half the cars coming off the line at the moment have a long roof.