I don't think I took apart much of my fairing, if at all, to get to the screw.
The screw is fairly small, phillips headed, and just holds the thin, chrome shell on.
I think it's slightly under the dead center of the back of the shell.
I'm looking at the Haynes manual. hard to tell.
I don't rmember major problems replacing the bulb, even though I have huge hands, and am a klutz.
Matter of fact, I initially put a red bulb in the tach, but didn't like it, and put a normal one in....so I've 'gone in there' about 3 times, although it's been about 3 years.....
There is a '96-2000 1200 service manual online you can access in the Members forum. MAy help to look at the tach.......