Finally, after ... 1 borrowed & returned laptop to confirm the tool was working; 3 OS re-installs on my old serial-port equipped laptop; half a dozen freeware/shareware OBD2 software installs & tryouts (they didn't all work); multiple e-mails back and forth with the tool vendor (was quite responsive and helpful):
Edit: cold start, trip around the block. The only downside: the programs that work with this tool and provide logging ability don't also report fuel consumption. So the SG will be a little out of whack when I disconnect it to do trials with the ODB2 tool.
Data exported as a text file, imported into Excel to use the charting utility. Dressed up a little further in Photoshop.