That little acrylic plug sucks, I've tried to use mine several times, same way, marked the timing mark, screwed the plug in deeper, finally just timed it with an open hole. I held my timing light just above the hole so it didn't too covered in the oil spray. It works better if you have a timing light that you can dial the timing mark into the hole, that way you're not fighting the oil mist for as long. Static is a good place to start, but getting the timing mark in the hole with the engine running is still the best, then you know you've got it right. That way you can also test your advance.