I decided to practice the neck joint with a piece of maple I had left over, because I was afraid to get it wrong and then not being able to undo the damage.
I went for a slotted design to stabilise the alignment. Used three M6 Rampa wood screw inserts.
This seemed to work fine, so I applied it to the Ziricote body…
…as well as the neck:
And here’s neck and body joined for the first time: