Jamie, your crosti is looking really good, I would not bother to paint the cab roof cream. I believe they may have been that curious brown that the LMR used for its cab interiors or just plain black. All the 9f"s I ever fired the cabs were pretty dirty inside. So when I prepped a loco I used to pour oil from the oil can over the boiler back in the cab let it run down everywhere then when I had finished doing dirty stuff get the prep pipe and wash the whole cab inside, over the boiler back, roof as well! You stood in the gangway to do this or get soaked but finished up with a nice clean footplate and a shiny boiler back. All dry by the time you made the tea and a happy clean driver,always a good thing! 9f"s best engines ever, except the rebuilt crosti"s which were dogs.