Admittedly I am not very good at gripping. Still I have been working up to gaffing in the year I have graduated since college. I find a lot of the terms you described to be familiar to me. Ruby 7 is a light (not sure watts) it is comprised of 7 smaller lights held together in an octagonal shape. It's one of the larger lights. A Space light is an over hanging light... a good example of a space light is perhaps from a couple scenes in the godfather where they would add some gel like Frost or Opal to also make the light soft. An Inkie, I think, is a very small light. Musco only rings a bell, and I need to brush up on how to balance loads (which I know is very important). As far as photometrics I can only assume you are referring to Color Temperature, f-stops, Focal Distance, and a few other things I am forgetting or are unfamiliar with.
Maybe I can't say I am experience, or professional. I can say with confidence however that I am component. The big thing right now is to memorize names (double riser, 1K, 2K, CTO, ect...) The film jargon in the East is different than here in CA.
I say I'll be a PA, Gaffer, or Grip because I've only been in LA for a little more than a month and am part of the 11.6% unemployed right now. I'll do any work I am offered. Perhaps if I reword it to something like this... "I am seeking work as a Gaffer, but am willing to work as a production assistant. I have a BA in film. I have done gripping, boom operating, and directing as well."