Very interesting thread everyone- it was searching Google for help with works instructions that brought me to this site by the way. Lots of useful hints, thanks.
I once read an article on Job Aids in Training and Development Journal- Job Aids and WIs are not exactly the same thing, I know. I guess WIs are an example of Job Aids. The article was by Bullock, well known in training circles, and he ended up with a job aid for planning or evaluating job aids. With an associate, I adapted it as part of a project on a post-grad course I was doing, and for what it's worth I attach it.