I'm currently between dummies, but I can tell you how to use them.
As far as forms go, there are the Jun Fan/Wing Chun sets and the JKD sets. The former are pretty similar between sifus. I've seen Randy Williams, some of Francis Fong's and have been taught the sets from the Inosanto clan (various instructors under Guro). They are pretty similar with a few differences here and there. Traditionally in the Historical JKD teachings, they only went up to #7 or #8, however, most of us in the Inosanto lineage know the full 10 sets.
As I understand it, Guro created what are called the JKD sets based on what Bruce Lee did on the dummy. These sets are very different from the Jun Fan/Wing Chun sets and are much more similar to the type of trapping done in JKD application (e.g. pak da, lop sao qua chuie, jao sao, etc.) These drills look like what you see in James Lee's book or Dan Inosanto's trapping definitive video. The JF/WC sets seem to work a different type of skill. A lot of the counter trapping techniques come from these sets. Also, some chi sao and other, what I call advanced skills, are found in the JF/WC sets.
While freestyling is probably the best way to train ultimately, there is a lot of good material in both sets. If you don't know what to freestyle, or if you want to put a check on your discipline and make sure you have a more comprehensive approach to your dummy training they are resource. Plus, like I said, there are some good tactical concepts inside the sets that can be extracted and applied.
As far as places to learn, Larry Hartsell has the first five JF/WC sets in his book on hardcore training. There are also several videos that have the sets, although some are more technically accurate than others. Ron Balicki's videos are good as well. One thing to remember is correct vectors in the techniques. The wing chun derived tools are very particular in the shape your body takes and the direction the tool moves.
