*gasp* Holy Canole gentlemen, that is an entire treatise on bulbs!
OK, let's say what I'm going to do: when I have some spare time I'll go get that flash unit and maybe another one if it's in decent condition. I'll order from J&C some M2, 5 and 25 bulbs and just see which ones fit where. I'll shoot some pictures with my Hawkeye using them, hoping I don't get blind in the process, and report back here with the results of the experiment.
Grosso modo, from what I can understand, there is a non-zero chance that at least one of these bulbs will fire, create light, and do so in time to expose a square of film. Technically, that counts as a picture
Edit: In the case that I have a type of bulb that does not fit my flash unit, what would be the safest way to dispose of it? I wouldn't realy care to send it to J&C, b/c of the shipping &c.