Here’s a great tip coming up with images for the Ben System:
On this subject, I would say that you don't necessarily have to blindly translate each spelling to an actual word. Just associating the spelling to something would be strong enough as long as the same association is made each time. For example if you have the spelling "neb" there isn't an english word for "neb" (not in my dictionary anyway!) but if you reverse the spelling you get "ben" (and an obvious link to a character!) as long as you do this each time you see "neb" occuring in your system it will do just as well as having a proper english word.
I’ve been doing something similar where I create new words for things. E.g., for me, 753 is “KAIM” which is “crime scene” (chalk outline on the ground) and 975 is “PEL” which is Apollo (“aPELLon” in one form of ancient Greek).