There seems to be four methods:-
a) supplied with kit or RTR model which often seem extremely thick
b) replace or solder in place some very thin (5') brass scale 2" wide around the boiler and firebox - all of whch is difficult to get a good result and may still be too thick
c) introduced by Alan Gibson many years ago and which I have used in the past - cuts strips of clear sellotape a scale 2" wide then attach these to the brass or plastic boiler direct or over a primer then adding painted lines or transfers on top
d) rely on transfers only, which still gives some impression of a band of steel in place.
My GC predilection moves me to the 4th option but does the community have any thoughts?

John