HI Alden,
Faster way would be to export the Job into a ATL file.
In the file there would be a Declare section example:-
DECLARE
GLOBAL $GV_VAR1 VARCHAR(10) ;
GLOBAL $GV_VAR2 VARCHAR(10) ;
You can update the length in this section, save and reimport the atl into the repo.
Regards,
Sandeep