Bad news. I do not believe this will work.
The Origen pin is thicker (2.91mm Origen vs. 2.16mm for the Magister) so it does not fit into the Magisters insulators which would have to be drilled out.
The Origen pin is shorter (non bf version but i assume them to be equal in length), 21,89mm vs. 23.5mm Magister. The length is an issue but could be workable, *but* the screwhead is also larger, which prevents it from sitting correctly in the insulator. If you dremeled the head down to a size that fits, you'd no longer have slots to install it correctly.
Lastly, the holes where the
juice exits on the pin, would be inside the Magisters deckpost which would need to be drilled as well. Since there is no sealing at the bottom and only the insulator to keep the
juice in at the bottrom, it would likely be a leaky affair. The pin would sit loosely inside the post, which would fill up with
juice.
I'd recommend getting a complete Origen and converting that more easily instead. If you enjoy the Magister you will most likely enjoy the Origen equally much. It's not leakproof like the Magister but as good or slightly better in all other regards.
Hope this helped.