Phono/preamp/amp chain. One of them tube the others SS. Which one?

Just trying to understand how low level detail on tube better vs. transistor. I haven't heard 70+db gain for LOMC all tube phonostages that don't have typical hissing noise not substantial via speakers, but quite audible via headphones.

The noise floor does not describe the amount of low level detail.  It turns out that the human ear has an exception to the masking rule in that it can hear into a noise floor of hiss. The jury is out on about how much- some say 20db but 10db seems no argument. If you listen to a tube phono section as opposed to a solid state unit of similar gain this difference in low level detail will be audible.

If you use an SUT then getting another 10-12db on the noise floor is easy.

If using a LOMC cartridge, my preference would be for an all-tube phono and line stage and a solid state amp, if the situation somehow was able to demand that one be solid state and the other tube.

I would not go with a solid state phono section. The thing that transistors don't do well is low level detail; IMO/IME you are better off with an SUT than you are a transistor input (better still if your all-tube phono section does not need the SUT all on its own). If you are going to loose detail, its best done by the power amplifier since if you loose it upstream, even the best amp and speaker won't make up for that loss.