Can I use my settings backup from 11 on 12?
Yes you can.
Thanks - Looking forward to it then... 
The settings backup should not be needed, but is a good idea just in case.
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You can install Opus 12 right over the top of 11 and the settings will be preserved. (Except font sizes, which get reset once, due to the new high DPI support.)
So you should only need a backup if you uninstall 11 first (which wipes your config), or if you want to go back to 11 after trying 12, or move to a new machine, and so on.
However, if you have customized a lot, it's always a good idea to make a config backup every so often, just in case, and right before installing a big update is a good time to do it. The backup you make will work in both Opus 11 and Opus 12.
(Note that going the other way -- loading a config or backup from Opus 12 into Opus 11 -- is not guaranteed. Configuration data from 12 will contain things which 11 did not understand.)