Here are some options. Install a Osram HSD 250/60 lamp in it that's going to get you down to 6,000K. It's not incandecent in
color temperature, but at least closer. At that
point perhaps you can install something like a
Rosco #3401, Roco Cinegel #3407, #3441, #3401 in front of the
fixture - given they don't just burn up.
Otherwise, given the
fixture has color filters and patterns, order a
dichroic filter to fit into one of the
pattern or filter slots. There is lots of suppliers out there that will custom make a filter to lower the
color temperature.
In any case, the dropping to a 6K color temp. lamp will be a good start to the solution.
Hmm, one has noted the problems of using moving lights for
incandescent sources.
Another solution that the above seems to be is that most of the above are in some way a amber coloring. Given two color wheels on the
fixture, perhaps one a amber and one the color of your choice will already solve the problem. Otherwise just color the
fixture in amber and see what it looks like when not white. It's probably not going to match no matter what you do unless the lamps are really ancient in any case.
You might also be able to
play with dimming the
fixture but I doubt it's able to do this more than 5%.