It's not currently possible for a user to change how many backups are saved, or what happens to the deleted ones, so if you want, you can put in that request.
However, for now, if I'm reading this correctly, your better option may be to turn off auto-backup, and perform manual backups when you make any major changes to your LaunchBox build. This way you'd have a master backup that will not change frequently that you know will be good if LaunchBox data corruption ever happens.