During the nascence of my enthusiasm for air-cooled Volkswagens, I often had occasion to help Melcher with his Beetles (a '63, a '74 Super, and a '71 Standard; none driven concurrently) in addition to my own car ('73 Fastback). We always used his timing light, a really good (re: expensive) one if I remember correctly. Certainly of a brand good enough to honor a lifetime warranty. Despite its pedigree, it had an annoying tendency to short out so you had to whack it once in awhile while using it, and even then it didn't always flash at each firing. It made timing the engine kind of annoying.
Hint: if you hook up your timing light and the engine stalls out when you pull the trigger, you have the red clip clamped to the wrong post on the coil.