Thanks for trying to provide some hints, it’s appreciated.
What I was looking for, as I clearly stated, is the opportunity to apply the rule directly to my header block.
You were providing some custom snippet, which probably won’t work throughout the various editor environments.
At least, I couldn’t make it work out of the box - but didn’t investigate further.
I’m pretty sure there is a solution somehow, but I’m currently not interested, as I’m using the widely used standard rule, which fits my needs, until or if there is a better solution available, which Louis hinted some time ago.