You know, I've never done it on a 7M, but I was actually thinking about it earlier today... how odd. I've seen gauges with EXTREMELY thin feelers; like 2" needles. I might have even inherited one in the past (I really need to go through my storage unit some time, but most of it is for big-rig diesels...).
I'm not sure specifically what info you're looking for. If it's for stock measurements this may help:
http://forums.toymods.org.au/index.php?th=19743&t=msg
http://www.mkiiitech.com/forum/showthread.php?t=152
If you're running aftermarkets or ground or welded cams and trying to measure them I can't suggest much other than to measure them out of the car or measure the valves from the inside with the head off.