Those additional windows on the cab sure would have been nice this past October while I was firing #487 during the fireman's school. We were set up with one student fireman in the seat, watching the track, train, & water level. The fireman instructor was standing behind them, between the tender & cab, and giving instruction to both them and the student working the scoop, while also watching the track ahead & train behind (the fireman has a lot to do). Since all the positions with a good view were occupied (the right side was occupied by the student & instructor engineers) I couldn't easily get a good view of the stack. Those little windows would have given me a better view so I could determine the color of the smoke, which would have given me some appreciated feedback regarding my effectiveness with the scoop.
I found that firing could be done one of two ways: You could work harder, or you could work harder & smarter. There was no easy way! (Having tried it out, warts and all, would I fire up Cumbres every day? If given the opportunity, YES!)
It's interesting to see early pics of K36 locomotives. They have been well-recorded in their later configurations, but not so much in their earlier incarnations.
Dave