Hey there, Jeroen! Nice to see you again. 🙂
Unfortunately, setting a default ticket header is something that isn’t supported at this time. It’s a great idea, though! If you have a moment, it would be great if you shared it on our UserVoice page. We track popular ideas for new feature to include in new releases and I can see how a default ticket header would be useful for others as well.
Does that help answer your question? Please let me know.
Cheers!
Geoff