In effect if you uses this plug-in often, it becomes tedious to reenter parameters
that will not change further; if I understand you correctly.
Another reason to muck with the 'register' function to solve this common problem.
1- Open 'Exifinfo_rb-en.py', the copy used by GIMP, with your text editor (gedit is OK with
display of line number).
2- For 'exiftool' at line 520 replace "/bin/exiftool" (Fedora) by the filename for your distribution
such as "/usr/bin/exiftool" in Debian XFCE.
3- Do something similar for the 'text_editor' at line 523 replace "geany" by the filename
of your choice of editor such as "/usr/bin/gedit".
4- Save the plug-in back. Restart Gimp. Now you have changed the default values of
of first two parameters sucessfuly if after starting 'Exifinfo_rb-en.py' you see 'exiftool'
and 'gedit' as values in the dialog.
Not sure that I should be the one answering your question since not at ease with English,
but was familiar with the plug-in.