4000-4500K is the equivalent of sunlight and has the best CRI. Anything 4600K or higher has a blue tinge, even on fluorescent replacements. 8000K actually appears bluer to the human eye than 6000K while also being noticeably dimmer at the same light output due to the wavelength difference. The higher the temp, the bluer they appear and the dimmer they get. That's not an opinion, it's literally the physics behind the Kelvin scale of light temperature.
I've already got H1/H4 conversion glass for my Challenger and '68 Valiant (all Hella), but I probably won't use the Challenger parts because the lens shape is different between the H1 glass and the H4. Appearance matters a lot to me on that car. I'm looking at Koito glass now, which ain't cheap but looks consistent across both bulb styles, though not OE. I'll stick with incandescent bulbs not only for the reasons I stated about the lights on Pete's '31 nor because they're widely known to cause serious electrical gremlins in modern cars and/or electronics due to EMI. It's also because LED and HID conversions are
illegal in the entirety of North America (and Europe, and Great Britain, and literally every other first-world country on Earth). If it's not a 100% factory setup, it's illegal. Period. A black vintage Challenger with a loud-ass yellow stripe will likely attract enough police attention without blue-tinged headlamps. The blue tinge is also illegal in all of North America for reasons unrelated to the conversion laws: Only law enforcement can have even a hint of blue in their lighting.
If you ever want to go down the rabbit hole of why LED and HID conversions suck
even though you perceive them as better, spend some quality time reading the tech information at
www.danielsternlighting.com. The man is exceptionally intelligent, which you may already know (he goes by "slantsixdan" at several other forums). What you may
not know is that he's been consulted by several foreign countries' governments and even the UN on the subject of automotive lighting, primarily forward lighting.