I would highly Recommend/suggest using tamaya clear green paint. Or orange for amber.(amazon or tamayausa.com (nfi)
I use this a lot to tint bulbs, marker lens, church windows, etc. easy peasy. Excellent self leveling..probably fairly easy to remove with a long detergent soak and a fingernail…
Or, since you want reversible, a superb alternative, albeit a bit pricey, is high quality theatre lighting gels. These are about 12”x12’ sheets.
I used to cut these and insert into the lgb markers. The accuracy of the color was notable. Really looked like that unique switch lantern blue-green lens. I found mine on ….amazon. Get high quality. There are cheap offerings that are simply colored vinyl. A total waste of money…how might i know this?
Imho, the tamaya is your best, cheapest and easiest option.
You should be able to leave the clerestory glazing in place and simply paint, either the entire glazing, or just the pane portion.
Despite AI, i recently researched this, for a couple of old REA g scale ‘sierra’ style coaches. My conclusion was that tinting was rarely used, especially on the late 1800’s coaches. Not pullmans, but jackson sharp, carter brothers, etc. clerestory glass, it seems from my research, was clear frosted. I did colored anyway, ‘cos i liked it. While i love the clarity of a colored glass, i made mine translucent to cut bulb glare at night.
But, i think the colored clerestory would add interest and look great. Bachmann uses rose colored translucent (not transparent )clerestory glazing. Looks great imho. Especially at night, the translucent colored clerestory catchs the interior roof lights, but not the blub glare. It can be very noticeable. You didnt ask, but imho, rose, or amber is more harmonious with the brighter white light that shines through the coach windows.
Best