"LE has no knowledge about the used kodi in an update "
I'm surprised but OK
"If something goes wrong with a nightly then restore your backup"
Simply restoring the backup means that the newly installed nightly remains in place so I need to do a clean install and then restore the backup. Earlier on (several months ago) I did try cloning the SSD to an HDD but whilst both were 120GB devices they wern't identical and even though I used clonezilla and told it to ignore the size difference (loads of empty space mainly) the clone would not work. If there's a better way I'd be grateful for being instructed.
"or stick to official release builds."
I would have done if they'd worked. I'm using the nightlies because they have fixed many of the problems I'd been having.
I know - I was in IT for a long time at both developer and manager level and I've seen some major bloodshed.
On a totally unrelated subject I did look at the SD burner and QT, I spoke to several people I'm still in touch with in the development community - the general feeling was if it involved QT run away quickly.