Restricting Numbers for Courses

Hi there - I think this is a great application but I am not that technically minded and I am struggling to figure out how to do the scripting in places. I am trying to set up a conference registration form where there are four different workshop slots during the day with around five choices of workshop per slot. I have set up the choice of workshop for each slot as a drop down menu. The tricky part is figuring out how to do the scripting so that when the maximum number of enrollments for each option has been reached, the person filling in the form is told that their choice of workshop is full and is asked to select again. To further complicate this, the maximum number would vary between workshops.

I thought I would use the getOccurenceCount script but really can't figure it out on my own. Can anyone give me a hand?