I just did one the other day
The center pin design is such that drilling was out of the question, IMO. The bottom contact pin screws into the post and the screw is so thin that I don't see anyway to drill it without deforming or coming through the side.
There were 2 insulators, top and bottom. The top one I used wire snips on to remove a small sliver out of, the bottom insulator didn't want to come off the pin so I left it on and filed a v into it and the pin using the corner of a flat file. I have a slight tremor in my hands which makes using a Dremel a bad idea.
It then screws back together lining up the v notch with the open section of the upper insulator.
I love the AFC on it, it works great and is easy to adjust. I've only had one build on it so far and the flavor is great for having such a large chamber.
Hope this makes some sense and is helpful.
I forgot, I also filed down the edge of the screw to open up the flow, when I go to re-coil it, I'll take some pics.