Northerner - Firstly, well done for standing up for your belief that storytelling can be a regular part of a folk club evening It Can be! but you're worrying me slightly. I've always found it best to pitch to the brightest. That way they don't feel patronised and anyone left behind might feel prompted to read up on a subject, or ask questions. Playing to those you feel may be less able or interested will alienate those who are bored by over simplification and if your audience is an adult one I'll bet the newcomers will realise things have been 'dummed down' for their benefit and still feel patronised. Even those you know to be less able or experienced may feel they are your peers and will appreciate bing treated as such. Of course, you can still fit in pieces of information that are unique to you by virtue of your experience in the field, but it is possible to do this as if you're just sharing with like-minded, informed people.
To my mind Jim Carroll has made the most pertinent comments here as there is a world of difference between the traditional tellers (particularly the Irish) and todays generation of childrens entertainers. I guess the best at the job will be able to change character as well as repertoire to do both jobs. Good Luck in your endeavours. You're doing all the right things by attending courses and listening to other people's experiences.