My 5S workshops are a half-day long.  There's no secret to that but it seems to fit well with the schedule of most small manufacturing plants.  In addition, I've found that it's about as long as folks can stick actively with 5S before wandering away. (If I need more time I simply schedule more half-days. I've had cases where I had to schedule full-day 5S workshops but they always reinforce for me why I like half-days  better.)

My basic format is:

1. Overview of 5S and its benefits (30 minutes)
2. Go to the shop floor to pick a focus area (15 minutes)
3. Go over the first three S's in detail (30 minutes)
4. Return to the shop floor and 3S away  (2 hours or so)
5. Return to the classroom for Standardize and Sustain overview (30 minutes)

I have materials for all this and, if I think of it, I'll post them at SlideShare.com.

I've got to run but next time I'll go into more detail as to what I do in each of the five sections.