I also highly recommend one of these
white balance lens caps . I would be sure you can get this brand in the US. They are cheaper than some of the big-name brands.
One shot with one of these under the lighting conditions you're in, set your camera's custom white balance using that shot, and you're away. It's not 100% perfect (I notice a slight blue cast on my Canon), but you can tweak it either in camera or in software later. And most of the time it's near enough to not worry.
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