White, peeled fuzi is more for earth dampness, which is why it’s in formulas like ZWT and FZT. Black fuzi is more for driving yang into water as in GJFZT. That being said, I generally just use the black fuzi all the time.

Rothgeb

You can still process FZ with the skin on, but the black FZ that ZZJ uses is unprocessed. But everything else you say is spot on. Though as Stephen Bonzak says I’m not sure how much difference it all makes, black is stronger and therefore warms fire more to generate earth and warm water so may as well just use the stronger one, though I’m sure that many fire spiriters will take umbrage at that assertion

F***ing hundreds!