I discovered a way to run in "EV" mode pretty easily.
At speeds greater than ~11 MPH, lifting the accelerator, then very lightly applying throttle evokes power from the battery only. There is some drag from the engine as it maintains compression, with the valves in the closed position, but downhill runs or efficient deceleration can be manipulated.
I haven't found much at all on driving this vehicle efficiently (or the highly technical aspects), so the plan is to compile some methods and information as a primer in developing a separate thread.
Other HI-2 owners are welcomed to add any info...
RH77