The default values were suggested by an operator of libera.
We don't rate limit the login process, nor parts and quits.  However, if you

paste a bunch of text and then part a channel, you will be spammed with a

bunch of "no such nick/channel" error dialogs.  I tried to work around this,

but the alternative just makes irc unresponsive until all the pasted messages

are sent.  That said, other messages are still delayed while these errors

dialogs are slowly popping up.

Lots