Got the script to update upon fontSize being changed, rather than having to reload the script.
In settings.java:
 - added onPreferenceChangedListener to listen to fontSize
 - overrode finish() to pack fontSize as return data if fontSize has been changed
In MainActivity.java:
 - moved script_lines[] to be private member data
 - added onActivityResult to parse data from settings.java and setTextSizes of script_lines[]