4129R,
I haven't tried a smaller bolt to see if things line up. The headlamps are out so I can get the back side of the bobbin in the body, I'll try it on the weekend.
And yes, I am very aware of the poor fitment of panels on plastic cars. I'm not aiming for a perfect fit, but one that's a bit better.
Tom,
The tape and marking is a great idea. The eccentric internal threaded bushing, i think, is a bit too much work. I'd rather mess with a plain hole than a threaded one.
Rod