Hi Malcolm,
This one is even more belated!!!
I'm fairly sure you will have moved on from this now. I still don't know the actual answer to your question, but I do remember you asking it. I also remember thinking that the trouble with the Dockstader software is that it isn't very interactive. IF it has a layout for the gear you are interested in, then it can give SOME help.
I've been attempting analysis of valve gear on an engine and searching for new (free) software to simulate 2D kinematics. I've come across this software for "Windoze" called "Linkage"……
**LINK**
This version has not been out long, and I've never seen it before. It has been designed to do any system of links, slides, pivots, gears and pulleys. I've found some situations where it can't calculate a geometry which ought to be physically possible. Generally though it's much more usable than the Dockstader software.
It has a bunch of examples built into it, and one of them is Stephenson's gear. Most of the examples are simplistic, or weird things like marble launchers.
The only thing I think that the Docstader software has over it, is steam diagrams and plots of the valve events. I'm still experimenting, but you might find inventive ways to achieve the same ends. In any case if you want to experiment with the overall geometry of a valve gear this is certainly worth a look.
Hope the O2 is going well…… (I guess you probably finished it by now!)
Andy.