which is pure lanolin, stinky sheep grease. Though it is a grease/lubricant, I've noticed on screws that I've undone since then, that it tends to harden up a bit over time, which surprised me. It didn't seem to be very "lubricant-like" after years.

I've never used TefGel. Scary to think of screws working there way out --being "lubricated out" so to speak-- under no load whatsoever!

Another idea for bedding screws (instead of Duralac or a grease like Tefgel or Lanakote) is to simply wrap the threads in plain old white Teflon plumbers tape. A bit more work, but once you get a system down, it's easy to quickly spin the tape around them. I've done that for lots of fasteners on my boat after seeing how the previous owner had done it, and it worked well. Stainless screws bedded for 15+ years in aluminum were fine.