Also made a fitting drilling jig. I took a 2 in. C-clamp and removed the threaded part. From here, I inserted a tube to guide the drill bit. Lastly, I drilled a hole in the bottom side and inserted a 3/16 pin.
When the fitting is in place, I put the pin in the hole on one side, the guide in the hole on the other side and drill away. This ensures that your holes line up correctly. Hope you see this jig in action soon!