My MythTV box odds and ends

I've been intensively updating my MythTV box this weekend thanks to the new card. Here's some tips that might help others.
1. If you change capture devices, don't modify the existing card, delete it and then add a new one.
2. The PVR series of cards can flag the aspect ratio of the source in the stream. This is set in the Recording Profiles frontend setup screen. I've now set up my card with extra profiles (I had to manually edit the database and patch MythWeb in order to achieve this) so that programs on widescreen channels no longer require me pressing W for the maximum quality.
3. DSMyth is pretty much mandatory for the Windows machines on the network, and thanks to the backend CPU being less busy recordings can stream from MythWeb.
Now more Gentoo-specific:
4. If you have your backend set to automatically switch off, and you want to update, make sure you have a shutdown check script which blocks on login shells, then (for bash) put ; exit after the command to run.
5. Be careful when updating. I managed to break ratpoison and php by updating readline. You can fix this by running revdep-rebuild after the update.
6. Always run etc-update to interactively update your config files after an update.