I'm happy to hear the restore resolved some of the issues. I have no idea why settings don't always get updated when you update to a new version of MC, I just know that it occasionally happens. And I have some good news for you… You can still retrieve your playlists that were overwritten when you restored the MC 24 backup, or any other tags related to those new 40 ripped discs for that matter.
When you do the restore option, there are two checkboxes. One is to restore the library and playlists, and one restores the settings. Most times, you are likely to want to restore both. For your prior issue, you needed to restore the settings, so you could get all your column widths back. But you must have also had the checkbox for library and playlists also ticked. So run the restore operation again, but this time, restore from the MC 29 backup folder and select the zip file closest to the date you last ripped a CD. Also, make sure the settings checkbox is NOT ticked this time. That should return you to the place you were after you ripped your last CD, but with the settings for the column widths maintained.
Another way to go about this more manually, but with complete control over what gets restored, is to use the following approach:
Navigate to the folder containing MC 29 backups - not through the restore option we did before, but using Windows Explorer. If you do not know where it is, go to options/file location/program options/library backups. It will either be the default location that MC sets automatically, or another place that you at one point designated. You will now see a bunch of zip files - choose the zip with a modified date that is closest to the date you ripped your last disc. Open another Explorer window and navigate to MC's current/active library. That will be located here:
C:\Users\your-user-name\AppData\Roaming\J River\Media Center 29\Library
Locate the windows side-by-side, and find the playlistx item. Drag-and-drop from the backup zip file to the active library (say yes to overwriting the existing file), and viola, the playlists that got overwritten by the MC 24 backup are now replaced with the MC 29 playlists you made after your last rips. Repeat this for any other fields/tags that you may have updated after ripping those last CDs but were overwritten by the previous restore operation. For example, you may have rated a number of those songs, or added lyrics, or keywords, or assigned genres… whatever. Just drag-and-drop the corresponding field files from the MC 29 backup to the MC 29 current library, and you should be back to where you were.
This can be very useful when you want to recover just certain fields from certain backups at certain points in time. This can be done across different versions of MC (like we did above for MC 24 and MC 29), or just among the various backup folders within a single installed version of MC.
FYI… You may have to do this as an admin - I am not positive, as I've always set up my user account with admin privileges.