I've got about 10 varieties set up in an aquarium to root & wondering what the ideal humidity would be.  Completely closed it's 100% of course.  I seem to recall someone saying 80-90% humidity was the ideal range.

I try to keep mine at 70-80%

I try to keep mine 70%-80% also, with 70%-75% being ideal IMO

And just because a compartment is totally sealed does not make it 100% humidity.  I run my bins sealed with a hygrometer inside for the first few weeks, and i'm usually in the 70%-75% humidity range.

Had a hygrometer in mine & it was reading 100% consistently for 2 days...  Seems like I better bring it way down.

I did a quick forum search for "humidity level" and got some really good results.  Here is one of the threads where this came up last time:  http://figs4funforum.websitetoolbox.com/post?id=4993650&highlight=humidity+level

I couldn't find the three or four other times a similar question was asked recently (I tried).  Every time, a new tidbit of info or clever bit comes up.  You may give a try at hitting search with other combination terms like humidity percent or humidity gauge to try and find others.