In my own kitbashes, I find that if I am going to need paint anything, I may as well paint everything. Try as I might, I can never get a "good enough" paint job on something as large as a plugged window. That being the case, if I were doing it, I think I would opt for squirrelhunter's option 2, which is to start with the 20thC obs. and add fluting. still a bit of window work to do, but the focus is likely to be on the big ones on the obs end, and those could be "factory" or pretty close. Plus, with the NYC obs, the configuration of the interior will be much closer (IIRC? or do they have the aisle on opposite sides?) to the "Royal" cars,