Thanks for your help, Lucas.
I used your suggestion in another thread for putting a dummy user profile into the User table and I now sideload my firmware updates instead of relying upon kobo's PC application or Wi-Fi. That leaves me to do whatever I want with the dictionaries and not worry about syncing messing up anything I've already installed.
Also, it's really nice to not have my ereader's "desktop" cluttered up by kobo's advertisements. I sideload all of the purchases I make from them anyway... So all's well that ends well.
Again, thanks for all of your posts on this forum.