If you must change the daily threshold, do it on a list-by-list basis,
don't change the LISTSERV default.  Simply set
 
* Daily-Threshold= x
 
Where x is the value you want the list to be held at.  Basically, if
the 50 message limit is only rarely exceeded, it would be even better
to leave it alone and issue the FREE xxxxxx-L command as needed.
 
Nathan