few comments already
- Is there a place where viewers will be able to download them scenes to further study your examples?
For the event "go", instead of trigger it via the fsm canvas, simply have it as a global transition over the state and mark the event "go" as "show in inspector, and then you can trigger processes right from the Unity inspector of that PlayMaker component.
Part 3: Why using a breakpoing on each state instead of stepping through with the debugger? just set a breakpoint on start state and then simply step through.
also, for catching errors, a vers good trick is to have a state with its name set to an empty string ( as many spaces as you want to have them uniquely named) and then put a breakpoing there, it will always be available if the error is triggered amd won't affect trouble free processes.
in general, if your xml turns out invalid, simply use online xml checkers to find where you have a typo or a wrong structure, it's very easy to mess an xml file when you edit it without a dedicated editor http://www.xmlvalidation.com/
for testing xpath, I often use http://www.xpathtester.com/xpath
I'll be editing the datamaker wiki and put links to your videos and all. Thanks again for your work on this!