Those concerns that you have re the Window surrounds have been pondering me too, but look at the pictire of No. 016 on post 33, have they been painted Creme? I have just gone through my pics off the Railcars and do not have a pic of 016 to see if this is so. May be worth a look.
Or:-
3 possible ways to replicate the windows may be:-
Kitchen Silver Paper - woild be very hard to get flat
Silver Foil Tape used ro secure Laminat Floor Underlay - same as above
Plasticard Window Inserts pre sparayed and put in after paintingbbody - Tricky with all those windows but I think maybee the best option.
All those windows are going to make whatever solution a pain. Some experimentation on a small mock section of windows me thinks.
JonD